Last updated: 9 September 2026
The difference between translation and localisation is straightforward: translation changes written content from one language into another while preserving its meaning, while localisation goes further by adapting that content for a particular country, region or audience. This can include language variants, tone, dates, currencies, measurements, cultural references and, for digital products, parts of the user experience.
In Ireland and the UK, the usual spelling is localisation; localization is the standard US spelling. Both terms describe the same concept. The important question is not which spelling you use, but whether your project needs straightforward translation, market adaptation, or both.
If you already know what you need, you can request a translation or localisation quote from TTC. If you are unsure, the comparison below will help you choose the right approach.
What Is the Difference Between Translation and Localisation?
| Area | Translation | Localisation |
|---|---|---|
| Main goal | Transfer meaning accurately from one language to another | Make content feel appropriate and natural for a specific market or locale |
| Focus | Words, meaning, terminology, tone and context | Language plus market, culture, formats, conventions and user experience |
| Typical content | Certificates, contracts, reports, manuals, correspondence and documents | Websites, apps, software, marketing campaigns, e-commerce and digital products |
| Examples of adaptation | Terminology and phrasing in the target language | Date and number formats, currency, units, imagery, calls to action, layouts and local search wording |
| Best when | The content needs to remain faithful to the source | The content needs to work naturally for a specific audience or market |
A simple way to remember the difference is this: translation changes the language; localisation adapts the experience.
What Is Translation?
Translation is the process of converting written content from a source language into a target language while preserving the original meaning as accurately and naturally as possible. A professional translator considers grammar, terminology, context, tone and the purpose of the text rather than replacing words one by one.
Translation is normally the right choice when the document itself must remain faithful to the source. Common examples include legal documents, business correspondence, technical material, academic records and personal documents.
For official documents, the required service may be a certified translation rather than a localisation project. A birth certificate, marriage certificate, diploma or police certificate, for example, normally needs an accurate translation that reflects the original document. It should not be creatively rewritten to sound more local.
You can learn more about TTC’s professional translation services or review common questions about document and certification requirements in our translation FAQs.
What Is Localisation?
Localisation is the adaptation of content, a product or a digital experience for a particular market or locale. Translation is usually part of that process, but localisation may also change elements that are not purely linguistic.
The World Wide Web Consortium describes localisation as adapting a product, application or document content to meet the language, cultural and other requirements of a specific target market. That can include numeric, date and time formats, currency, symbols, colours, address conventions, layout considerations and other local expectations.
This is why a website can be translated correctly and still feel foreign to its users. The words may be accurate, but the currency may be wrong, the date format unfamiliar, the call to action unnatural, or the examples and references irrelevant to the intended audience.
For projects such as websites, software, apps and multilingual marketing, see TTC’s localisation services.
What Does Localisation Change Beyond the Words?
The exact scope depends on the project, but localisation can include several layers.
Language Variants and Terminology
The same language can differ significantly by market. English for Ireland, the UK and the US may use different spelling, vocabulary and conventions. Portuguese may need to be adapted for Portugal or Brazil. Spanish may need a specific regional variant depending on the audience.
A localisation brief should therefore identify the target locale, not just the language. “Portuguese” may be too broad if the real target is Brazilian Portuguese for customers in São Paulo, while “English” may be too broad if the product is specifically for Irish users.
Dates, Numbers, Currency and Units
People expect familiar formatting. Dates can be ordered differently, decimal and thousands separators vary, currencies change, and measurements may use different systems. Unicode’s Common Locale Data Repository exists because these conventions vary across languages and regions and are important to software and digital products.
Tone, Idioms and Cultural References
A phrase that works well in one market may sound awkward, overly formal, too casual or simply confusing in another. Humour, idioms, slogans, examples and cultural references often need adaptation rather than literal translation.
Images, Layout and User Experience
Localisation can also affect non-text elements. A website or app may need different imagery, text lengths, field formats, payment references or navigation behaviour. Languages that use right-to-left scripts may require additional layout considerations.
Search Behaviour and Multilingual SEO
Users in different markets do not always search using literal translations of the same keyword. A phrase with high search demand in English may have a completely different natural equivalent in French, German, Portuguese or Spanish.
For a multilingual website, keyword research should therefore be performed for the target market rather than translating an English keyword list word for word. Page titles, headings, internal links and on-page copy should use the vocabulary real customers use in that locale. Technical elements such as language targeting and hreflang should also be reviewed by the website or SEO team.
Translation vs Localisation: Practical Examples
| Project | Usually Needs | Why |
|---|---|---|
| Birth certificate for official use | Translation / certified translation | The translated document should faithfully reflect the source; creative market adaptation would normally be inappropriate |
| Legal or business contract | Translation | Accuracy, terminology and fidelity to the source are usually the priority |
| Marketing website entering a new country | Translation + localisation | Language, calls to action, examples, currency, terminology and local search behaviour may all need adaptation |
| Mobile app or software interface | Localisation | Text must work in the interface, while dates, numbers, currencies, layouts and user expectations may vary by locale |
| Advertising slogan or campaign | Localisation or transcreation | The message may need creative adaptation to preserve its effect rather than its exact wording |
| E-commerce product pages | Translation + localisation | Product language, measurements, currency, delivery information and customer terminology may differ by market |
| Technical manual used internationally | Translation, sometimes with localisation | Core instructions require accurate translation; units, warnings, interfaces or regional references may also need adaptation |
When Do You Need Translation, Localisation or Both?
Ask these questions before choosing a service:
- Is the content an official or formal document? Translation, and sometimes certification, is usually the priority.
- Will the content be used to sell, persuade or engage customers in a specific country? Localisation is more likely to add value.
- Does the content contain prices, dates, measurements, addresses or market-specific terminology? These elements may need localisation.
- Is the content part of a website, app or software product? Plan for localisation rather than text-only translation.
- Does the same language have important regional variants? Define the target locale before work begins.
- Would a literal translation preserve the meaning but lose the intended effect? Localisation or transcreation may be more appropriate.
Many projects use both. The translation provides the accurate linguistic foundation, while localisation makes the result appropriate for the people who will actually use it.
If your project involves a website, app, software interface or marketing content, explore TTC localisation services and send us the target language, target market, file or URL, and intended use so the scope can be assessed correctly.
What About Transcreation and Internationalisation?
These terms are related but describe different parts of the process.
Transcreation is a more creative form of adaptation often used for advertising, slogans and brand messaging. The goal is to recreate the intent, emotion and persuasive effect for the new audience rather than stay close to the original wording.
Internationalisation, often abbreviated as i18n, happens earlier in the product or development process. It means designing a website, application or product so that it can be adapted more easily for different languages and locales. Localisation is then the market-specific adaptation.
For digital products, thinking about internationalisation before translation begins can reduce avoidable rework later.
Why the Difference Matters for Businesses
Choosing the wrong approach can create two opposite problems. A company can spend money localising content that only needed faithful translation, or it can translate customer-facing content accurately but launch it in a form that still feels foreign to the audience.
Defining the project correctly at the beginning helps determine what needs to remain faithful to the source and what can or should change for the target market. It also helps translators, reviewers, developers, marketers and project managers work from the same brief.
For a localisation project, useful briefing information includes the target country or region, target audience, language variant, content type, platform, brand terminology, preferred tone, technical file format and launch deadline.
How TTC Approaches Translation and Localisation Projects
TTC Translation Services provides professional translation and localisation support across more than 200 languages. TTC operates ISO 9001 and ISO 17100-certified translation quality processes and works with qualified linguists across a range of subject areas.
The appropriate workflow depends on the project. A certified personal document requires a different approach from a multilingual website, marketing campaign or software interface. For that reason, the first step is to define the language pair, target locale, intended use, file format and deadline before confirming the scope.
For business and digital projects, localisation requirements should be agreed before translation begins so that terminology, market adaptation and review expectations are clear from the start.
Frequently Asked Questions
Is localisation the same as translation?
No. Translation converts written content from one language into another while preserving meaning. Localisation normally includes translation but also adapts content for a particular market or locale, which may include terminology, date and number formats, currency, cultural references, imagery and user-experience elements.
Is a certified translation a form of localisation?
Usually not. Certified translation is focused on producing an accurate translation of a document together with the required certification statement or formalities. Localisation is designed to adapt content for a market or audience. Official documents generally need fidelity to the source rather than creative adaptation.
Is website translation the same as website localisation?
Not necessarily. Website translation changes the written language. Website localisation can go further by adapting calls to action, terminology, currency, formats, images, local search wording and other market-specific elements so the website feels natural to its intended audience.
Which spelling is correct: localisation or localization?
Both are correct. Localisation is the standard spelling in Irish and British English, while localization is the standard spelling in American English. They refer to the same process.
Do I need localisation for different versions of the same language?
Sometimes. Regional versions of the same language can differ in spelling, terminology, tone, legal or commercial conventions and user expectations. If the content is customer-facing, it is often worth defining the specific target locale rather than treating the language as one universal version.
Need Translation or Localisation?
Understanding the difference between translation and localisation can help you choose the right service for your project. If you are still unsure, send TTC the content or file, source language, target language, target country or audience, intended use and deadline. We can then assess whether straightforward translation, localisation or a combination of both is the appropriate scope.
Request a translation or localisation quote or contact TTC to discuss your project.
External reference: W3C: Localization vs. Internationalization.
