If you’ve ever Googled “what is i18n?” or paused mid-project to figure out how to create a TMX file, you’re not alone.
The localization world is full of acronyms, technical terms, and phrases that can feel confusing — even if you’ve been in the industry for a while. So we’ve put together this localization terminology glossary to help. It covers everything from the basics (like translation vs. localization) to more technical concepts (like pseudo-localization, fuzzy matches, or XLIFF).
This practical, detailed and up-to-date guide is here to make localization terminology easier to understand — and more useful in your day-to-day work.
0-9
101% match
A translation that is exactly the same as a previous one, including its context.
Use case: Used to repeat the exact same sentence in the same situation.
Example: A support article that’s been updated but remains identical in wording and context.
A
Adaptation
Changing content to fit local culture or habits.
Use case: Used to make content feel natural to people in different countries.
Example: Changing a winter holiday ad for Australia to show summer imagery instead of snow.
Agile localization
Adding translations during each stage of product development.
Use case: Used to keep translations in sync with regular product updates.
Example: Translating new app features every sprint instead of waiting for a full release.
AI translation
Translation done by artificial intelligence trained on large amounts of language data.
Use case: Used for fast, high-volume translations when speed is more important than perfect style.
Example: Using AI to translate thousands of product listings, then reviewing key ones manually.
API (Application Programming Interface)
A tool that lets software programs talk to each other.
Use case: Used to send text for translation automatically from your app or website.
Example: Connecting your CMS to a TMS using an API so content is sent for translation instantly.
B
Back translation
Translating text back into the original language to check its meaning.
Use case: Used to double-check that a translation is correct.
Example: Translating a clinical trial consent form from English to French and back again to catch errors.
C
CAT tool (Computer-Assisted Translation tool)
Software that helps translators work faster and stay consistent.
Use case: Used to suggest previous translations and save time.
Example: Using Taia’s CAT tool to auto-suggest how to translate a recurring sentence.
CMS (Content Management System)
Software used to create and update website content without coding.
Use case: Used to manage content in multiple languages more easily.
Example: Translating and publishing blog posts from WordPress using a plugin.
Collaborative translation
Several people working together to translate content.
Use case: Used when large projects need to be done quickly.
Example: A marketing team and translators using Smartcat to co-edit translations in real time.
Concordance search
Searching for how a word or phrase was translated before.
Use case: Used to keep word choices consistent across different texts.
Example: Looking up how “account” was previously translated in your TM—was it “cuenta” or “perfil”?
Continuous localization
Automatically translating content as it’s created or updated.
Use case: Used when new features or updates are released often.
Example: An e-commerce site localizing new product pages as soon as they go live.
Culturalization
Changing content to match the local culture more deeply.
Use case: Used to make sure content is not confusing or offensive.
Example: Rewriting a slogan so it makes sense in Japan, not just translating it directly.
D
DNT (Do Not Translate)
A note saying that a word should stay in the original language.
Use case: Used for things like product names or trademarks.
Example: Keeping “iPhone Pro Max” untranslated in all languages.
DTP (Desktop Publishing)
Adjusting document layout or format after translation so it still looks good.
Use case: Used when translated text is longer or shorter than the original, or when it’s in a design format.
Example: Resizing layout in a French brochure to fit the longer sentences.
F
Fuzzy match
A close but not exact match to something already translated.
Use case: Used to reuse parts of old translations to save time.
Example: TM suggests “Sign in to your account” for “Log in to your account.”
No credit card or verification required.
G
GILT
A short way to say globalization, internationalization, localization, and translation.
Use case: Used to describe the whole process of going global with content.
Example: A SaaS team planning its GILT strategy before expanding into Europe.
Globalization (G11N)
Preparing content or products to work well in any country.
Use case: Used before translation to make content flexible for different markets.
Example: Designing your checkout to support multiple currencies and languages from the start.
Glossary
A list of important words and how to translate them.
Use case: Used to make sure terms are translated the same way every time.
Example: Ensuring “support ticket” is always translated as “chamado de suporte” in Brazilian Portuguese.
GUI (Graphical User Interface)
The parts of software you click, tap, or see on screen.
Use case: Used to translate buttons, menus, and messages in apps and websites.
Example: Translating a “Submit” button into “Enviar” for Spanish users.
H
Hybrid translation
A mix of AI translation and human editing or review.
Use case: Used to speed up translation while keeping quality high – machines do the first draft, humans refine it.
Example: AI translates a user manual, and a human linguist edits it to ensure accuracy and clarity.
I
In-context translation
Seeing how the text looks in its real place while translating.
Use case: Used to avoid awkward or confusing translations.
Example: Viewing the word “Home” in the header of a webpage during translation.
International SEO
Helping websites rank well in search engines in different countries.
Use case: Used to bring more people to a localized website through search.
Example: Optimizing titles and keywords like “comprar zapatos” for Spanish-speaking users in Mexico.
Internationalization (I18N)
Designing products so they’re easy to translate later.
Use case: Used to prepare software for multiple languages before translation starts.
Example: Moving all text out of the code and into a language file.
K
Keys
Labels used in software to show text in different languages.
Use case: Used to connect a translation to the right spot in an app or website.
Example: Using a key like btn.submit to display “Submit” in English and “Soumettre” in French.
L
Language code
A short code for a language, like “en” for English or “fr” for French.
Use case: Used to tag content and files with the right language.
Example: “de-DE” stands for German as spoken in Germany.
Language pair
The two languages used in a translation, like English to German.
Use case: Used to describe what languages a translator works with.
Example: EN–JP is a language pair for English to Japanese.
Language Service Provider (LSP)
A company or freelancer that offers translation and localization.
Use case: Used when you need help with professional translation.
Example: Hiring an agency to localize your website and legal content.
Literal translation
Translating word by word, without changing grammar or meaning.
Use case: Used for technical or legal content, not everyday writing.
Example: Translating “kick the bucket” literally instead of using the equivalent idiom for “die.”
Locale
A language and region combination, like French (Canada).
Use case: Used to adjust spelling, dates, or currency for local users.
Example: Using “fr-CA” instead of “fr-FR” for Quebec-specific French.
Localization (L10N)
Translating and adapting content for a specific place or audience.
Use case: Used to make websites, apps, and content feel local.
Example: Changing currency symbols and translating product pages for the UK market.
Localization ROI
The return on investment you get from localizing content, products, or experiences.
Use case: Used to measure whether localization efforts lead to more users, sales, or engagement in new markets.
Example: A company spends $5,000 localizing its app for Germany and sees a $25,000 increase in revenue from that region.
Localization testing
Checking if a translated product works and looks right.
Use case: Used to catch layout problems or missing translations.
Example: Testing a mobile app in Arabic and finding a button overlaps with the text.
M
Machine Translation (MT)
Automatic translation done by software like Google Translate.
Use case: Used for fast translation of lots of content.
Example: Translating 10,000 product listings into Spanish using AI.
No credit card or verification required.
Markup language
Code that adds formatting to text, like HTML or XML.
Use case: Used to structure content on websites or apps during translation.
Example: Translating the content inside <h1> tags but leaving the tags untouched.
Multilingual workflow
A system for handling translation into many languages at once.
Use case: Used by global companies to manage content across markets.
Example: Automatically sending blog posts to be translated into 12 languages on publish.
N
Natural Language Processing (NLP)
AI that helps computers understand and use human language.
Use case: Used to improve machine translation or analyze text.
Example: Using NLP to detect spam in different languages.
Neural Machine Translation (NMT)
A smarter kind of machine translation that uses AI to improve quality.
Use case: Used in tools like DeepL for smoother and more accurate translations.
Example: Translating complex sentences with better grammar and context using NMT.
NMTPE
Human editing of AI-generated translations to improve quality.
Use case: Used to combine speed of AI with accuracy of a translator.
Example: A human translator reviewing machine-translated product descriptions before publishing.
O
OCR (Optical Character Recognition)
Technology that turns scanned documents or images into editable text.
Use case: Used when you need to translate content from PDFs or scanned contracts.
Example: Converting a scanned product manual into translatable text.
Over-the-Air (OTA) updates
Sending translation updates directly to an app or product without a new release.
Use case: Used to quickly push fixes or improvements to localized content.
Example: Updating a mistranslated button in a mobile app without publishing a full app update.
P
Pluralization
Making sure translations correctly handle singular, plural, and other number-related forms.
Use case: Used to avoid awkward text like “1 items” or “0 message.”
Example: Translating “You have 3 new messages” into Russian, which uses different word forms for each number.
Post-editing
Fixing and improving machine-translated text by a human translator.
Use case: Used to make sure AI-generated translations sound natural and accurate.
Example: A linguist reviews machine translations of marketing emails before sending.
Proofreading
A monolingual review of the translated text to correct grammar, spelling, or flow — usually done by a native speaker.
Use case: Used as a final polish to catch surface-level issues before publishing.
Example: A native German speaker proofreads a translated brochure to fix typos and improve sentence flow.
Pseudo-localization
Testing your app or site by replacing text with fake characters before actual translation.
Use case: Used to check if layouts break or if text expansion causes issues.
Example: Displaying “[!!! Tèxt Êxpánded !!!]” in the UI to test spacing and encoding.
Q
Quality Assurance (QA)
Checking translations for errors, consistency, and formatting.
Use case: Used to make sure nothing was missed or broken during translation.
Example: Running automated QA checks to flag untranslated strings or incorrect tags.
R
Regional content preferences
Customizing text, visuals, or tone for specific regions within the same language.
Use case: Used to make content feel more familiar to local users.
Example: Using “color” for US English and “colour” for UK English.
Revision
A bilingual review of a translation that compares the source and target text to check for obvious errors in formatting or language.
Use case: Used to ensure the translation is faithful to the original and free of errors.
Example: A reviser checks a French translation against the original English document to correct any errors or inconsistencies.
Right-to-Left (RTL)
Languages that are read from right to left, like Arabic or Hebrew.
Use case: Used to adjust layout, alignment, and icons to work in RTL mode.
Example: Flipping navigation menus so they flow right-to-left in Arabic.
S
SDK (Software Development Kit)
A collection of tools that help developers build and localize apps.
Use case: Used to add localization features or send text for translation.
Example: Using an SDK to connect your app to a translation platform.
Segment
A unit of text (usually a sentence or phrase) that’s translated individually.
Use case: Used in translation tools to break content into smaller, manageable parts.
Example: Translating “Add to cart” as one segment in a product UI.
Segmentation
Breaking content into separate segments for easier translation.
Use case: Used to organize text logically and improve translation memory matches.
Example: Splitting a long paragraph into 3 sentences for easier reuse and quality control.
Simship (Simultaneous shipping)
Launching your product or content in all markets at the same time.
Use case: Used to ensure a global product launch happens without delays.
Example: Releasing a new game in English, Japanese, and Spanish on the same day.
No credit card or verification required.
Source file
The original file that contains the text to be translated.
Use case: Used as the base for creating all translated versions.
Example: A Word document with the original English version of a report.
Source language
The language the content is originally written in.
Use case: Used to define the starting point of any translation project.
Example: English is the source language for a website being translated into French.
String
A piece of text (word, phrase, sentence) used in code or content.
Use case: Used to define what needs to be translated in software or websites.
Example: A string like “Forgot password?” appears in the login UI.
Style guide
A document with rules on tone, voice, formatting, and preferred terms.
Use case: Used to keep translations consistent and on-brand.
Example: Telling translators to avoid contractions or use formal tone in legal content.
Subtitling
Adding translated text to video content.
Use case: Used to make videos understandable for viewers in other languages.
Example: Subtitling a product tutorial video in Japanese.
T
Target language
The language you are translating into.
Use case: Used to define the language of the final translated version.
Example: Translating from English to Italian—Italian is the target language.
TEP (Translation, editing, and proofreading)
The language you are translating into.
Use case: Used to define the language of the final translated version.
Example: Translating from English to Italian—Italian is the target language.
Termbase
A database of important terms and their translations.
Use case: Used to keep translations consistent across teams and projects.
Example: Always translating “Terms of Service” the same way in every language.
Terminology management
Controlling how certain words or phrases are translated.
Use case: Used to avoid confusion or mistranslation in key parts of content.
Example: Making sure “account” always means a user profile, not a financial term.
Time zone localization
Showing dates and times in the user’s local format.
Use case: Used to avoid confusion for global audiences.
Example: Showing a meeting as 9 AM EST for US users and 3 PM CET for European users.
TM (Translation Memory)
Translation memory is a database that stores past translations for reuse.
Use case: Used to speed up future translations and keep wording consistent.
Example: Auto-suggesting a past translation of “Contact support” for reuse.
TMS (Translation Management System)
Software that helps organize, assign, and manage translation projects.
Use case: Used to automate file handling, track progress, and collaborate.
Example: Using a TMS like Phrase or Lokalise to manage app localization.
TMX File (Translation Memory eXchange)
A standard file format used to store and share translation memory data.
Use case: Used to move translation memory between different tools.
Example: Exporting a TMX file from an LSP and importing it into Taia for a new project.
Transcreation
Adapting a message for another culture while keeping its intent, tone, and impact.
Use case: Used for marketing copy or brand slogans that need more than translation.
Example: Turning “Just do it” into a locally powerful version that still inspires action.
Transcription
Writing down spoken audio as text in the same language.
Use case: Used to create subtitles, captions, or scripts for translation.
Example: Transcribing a webinar before translating it into German and Spanish.
Translatability
How easy a piece of content is to translate well.
Use case: Used to plan or write content that avoids idioms or complex phrasing.
Example: Rewriting “hit the ground running” to something more universal like “start quickly.”
Translation
Changing text from one language into another while keeping its original meaning.
Use case: Used in every step of making content understandable to a new audience.
Example: Translating a product catalog from English to Polish.
Translation memory leverage
How much of your content can be reused based on past translations.
Use case: Used to estimate effort and cost before starting a new translation project.
Example: If 70% of a document is already in your TM, only 30% needs to be translated.
U
UI localization
Translating and adjusting the software interface for different languages.
Use case: Used to make sure apps are fully usable and clear for all users.
Example: Translating navigation menus and error messages in a CRM platform.
User-generated content (UGC) localization
Translating or moderating content written by users.
Use case: Used in social platforms or review sites to support global audiences.
Example: Translating customer reviews into multiple languages on an e-commerce site.
V
Voiceover localization
Recording voice in another language to match original audio or video content.
Use case: Used in product videos, ads, or e-learning modules.
Example: Dubbing a product demo video from English into Korean.
X
XLIFF (XML Localization Interchange File Format)
A standard format for exchanging localization files between tools.
Use case: Used to move translation files between systems while keeping structure intact.
Example: Exporting a set of website strings from a CMS in XLIFF format for translation.
XML (Extensible Markup Language)
A format that holds structured data, often used in translation workflows.
Use case: Used to organize and deliver content in a format translators and tools can read.
Example: Translating product data stored in XML files.
Final thoughts
Localization can feel like a different language in itself. This glossary is here to make it easier. Whether you’re new to the field or just need a quick reminder, it’s a handy guide to help you work smarter and speak the same language as your team.
Bookmark it. Use it. Share it.
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Eva Legovic
Frequently asked questions
What is the difference between localization and translation?
Translation is about converting words from one language to another. Localization goes further—it adapts content to fit the culture, tone, and expectations of the local audience. Think of it as the difference between speaking the language and speaking their language.
What does i18n and l10n stand for in localization?
They’re numeronyms—shortened forms that use numbers to represent how many letters are in the middle of a long word.
i18n = internationalization (or internationalisation in British English)
l10n = localization (or localisation in British English)
There are 18 letters between the “i” and the “n” in internationalization, and 10 between the “l” and the “n” in localization.
And yes, it’s a bit geeky—but super common in tech and localization teams.
What is a translation memory, and how does it work?
A translation memory (TM) is like your project’s memory bank. It stores past translations and reuses them when similar content shows up again. So instead of re-translating “Add to cart” 200 times, your TM says, “Hey, I’ve got this.”
What does a CAT tool do in the localization process?
CAT tools (Computer-Assisted Translation tools) help translators work faster and more consistently. They break content into chunks, suggest past translations, and highlight terms from your glossary. Think of them as the translator’s version of spellcheck + autocomplete + Google Docs.
What is a fuzzy match in translation memory?
It’s a “close but not exact” match found in your translation memory. If you previously translated “Create your account,” and now you’ve got “Set up your account,” the tool might suggest a fuzzy match so you don’t start from scratch.
How does continuous localization help agile teams?
It keeps translations flowing while your dev team builds. No more stop-and-go between releases—your content gets localized automatically as features are updated. It’s like continuous delivery, but for language.
What is the role of a language service provider (LSP)?
An LSP is a company (or freelancer) that handles your translation and localization needs. They match your project with translators, manage workflows, do quality checks—all the stuff you’d rather not juggle yourself.
What is a fuzzy match in translation memory?
It’s when the system finds a segment that’s similar to what you’re translating — just not 100% identical. Instead of retyping everything, you tweak it slightly. It’s one of the easiest ways to save time (and budget).
What is the difference between revision and proofreading?
Revision checks both the translation and the original to make sure everything matches. Proofreading just looks at the translation and fixes grammar, typos, or weird phrasing. One compares; the other polishes.
How do I calculate localization ROI?
Easy version: compare what you spent on localization with what you gained (more users, more sales, more engagement).
Example: Spend $5,000 to localize your app for Germany. Make $25,000 in new revenue. That’s a nice ROI.
What’s the benefit of hybrid translation over traditional methods?
Hybrid translation combines AI translation with human editing. You get the speed of AI plus the quality of a pro translator. It’s faster and more affordable—without sacrificing accuracy (especially if you’ve got a solid TM and glossary backing it up).
