What Is Localization Testing?

August 19, 2020
What Is Localization Testing?

I believe that localization testing is one of the least understood areas of the software localization process. Or perhaps not the least understood, but simply the least well known! Over the years I’ve worked with a wide range of clients on software localization projects and the localization test process has been new to many of them. Hence this step by step guide to what localization is and how it works. 

Localization Testing – Defined

The sensible place to start is with a definition of localization testing. It’s a question I’m commonly asked by clients who are new to Tomedes’ software localization process: What is localization testing? 

Localization testing is a key part of the software and website localization process. It takes place when a piece of software or a website is being localized for use in a new language and/or region. A localization tester performs tests on it to ensure that the key fundamentals function properly. 

The localization test process considers both the content of the software and the user interface (UI). It takes place after the localization has been carried out, in order to check that the product works perfectly for the intended audience. 

I think it’s worth noting here that localization testing is different to globalization testing. The latter tests that the website or software will function in any language or culture, whereas localization tests are specific to it working in one region or language only. You can read more about the differences between localization, internationalization and globalization by clicking the link below.

Read more: What Are Localization, Internationalization and Globalization?

Key Factors to Consider on Your Localization Test

Your localization test will review various fundamental aspects of the software’s functionality. Successful localization testing means that the software will work well for its intended users. On the other hand, if the localization test turns up any bugs or other issues, these can be addressed prior to the product being finalised. This is what makes localization testing such a valuable part of the localization process. 

Speaking of localization, it’ important to understand just how technical a task the process is. Before source files can be localized, they need to be internationalized. The internationalization coding standard – known as i18n – involves turning source files into strings that can be prepared and extracted ready for localization. Localization, by the way, is known as l10n. 

You’ll need an experienced localization tester who is familiar with a range of localization testing tools. The tester will use a detailed, step-by-step approach to ensuring that the software or website delivers everything it should in terms of localized content and that the user interface works as intended. This will include:

  • User interface: This is a huge area of work during the localization process and one that warrants careful testing. An example of user interface localization includes changing the design elements of a website to accommodate a new text direction. English is read from left to right; Arabic from right to left. As such, an English website that is being translated and localized for an Arabic audience will need to factor a change in text direction into the design. The functionality of this will then need to be part of the localization test. 

  • User experience (UX): Different countries use different formats for dates, addresses, measurements, currencies, quotation marks and so forth. Consider, for example, the difference between question mark placement in English and Spanish. In English, the question mark is at the end of the sentence; in Spanish, it’s at the end of the sentence but also inverted at the beginning of it. Different countries also use different keyboards with special characters, such as accents, which have to be factored into the localization process and subsequent testing in order to deliver appropriate UX functionality. 

  • Language: Localizing a piece of software or a website doesn’t just mean picking the right language and ploughing ahead with the translation – it’s more complicated than that. Many languages have multiple variations. If you’re translating software into Spanish, for example, do you need ES (the Spanish spoken in Spain), ES-MX (Mexican Spanish) or ES-CO (Colombian Spanish)? The localization testing process will double check that such requirements have been implemented and that the software functions according to the particular variation/dialect required. 

  • Script: Tied in with language is the issue of script. There are hundreds of different writing systems (scripts) in use around the world. These can be alphabetic, such as the Latin alphabet or Greek alphabet. They can be pictographic/ideographic, such as Adinkra. Scripts can also be logographic, such as Egyptian hieroglyphs or Chinse Hanzi characters. Scripts can also be syllabic, segmental and more. The localization testing process needs to ensure that the software or website works with the required script in every way, from the user interface to the content. 

  • Local regulations: Complying with local legal requirements can be a huge area of work. These will differ depending on the nature of the software or website, but common examples are the need to comply with data privacy laws and cookie usage legalities in the territory in question. If you are going to process data in the EU, for example, you’ll need to comply with the requirements of the General Data Protection Regulation (GDPR). This will have operational implications for your software or site, which will need to be factored into the localization process and the localization testing. 

  • Cultural considerations: Every culture has its own take on everything from religion to philosophy to superstition. This often gives rise to things such as sacred symbols or colours that hold particular importance. Certain symbols can also be highly offensive or even illegal – consider the Confederate flag in the US or the swastika in multiple countries. Localization testing needs to factor in these cultural considerations. 

  • Imagery: Photographs and icons have to fit the expectations and subtleties of the target culture. Websites, for example, need to use images that reflect those the site is aimed at. Icons, meanwhile, need to be designed to suit the intended audience, from their colours to their style. This is all part of the localization process and therefore has to be reviewed as part of localization test procedures. 

For further details of what’s involved in website localization and thus what needs to be tested for, you can click the link below. 

Read more: Website Localization – The Complete Guide

Do you want to watch a video instead? We got you covered.


Performing Your Own Research Vs Localization Services for Your Testing Insights

I find that those who are new to the concept of localization testing often assume that it’s something they can undertake themselves. While this can be done, by a company that’s prepared to undertake relevant research into what its software or website will need to deliver to meet the needs of the target audience, there are certain advantages to using a professional localization service. 

I think it’s worth quickly exploring each of these approaches. 


Is your company the sort that likes to take or keep things in-house wherever possible? If so, a research-based approach to localization testing may be your preference. This is where you find out for yourself what you need to do and have an in-house localization tester and localization testing tools. 


If you’re already familiar with the localized requirements needed for your software or website, then researching how to test the localized version and testing in-house may prove a more cost-effective option than using a professional localization agency. 

This approach also has the advantage of saving the time it takes to find and engage a localization company and then bring them up to speed on your product and requirements. Your company should already hold all of this knowledge and thus be able to kick-start localization testing fairly rapidly. 


A lack of in-house understanding and experience can end up leading (at best) to wasted time during the localization testing process. At worst, it can result in the failure of that process to identify fundamental flaws in the software or website’s functionality. This can negatively impact the product’s reception in the target region and potentially damage the company’s reputation. 

Lack of cultural knowledge also comes into play here. Those testing the software must be experts in the region that it’s being localized for. If they’re not, it’s all too easy to overlook certain fundamental details. 

Localization Services

The other option is to use professional localization services to undertake the localization testing process for you. This approach also has various advantages and disadvantages, though on the whole I would say it usually wins out over the in-house approach.  


A decent localization service will be able to provide experienced localization testers, who can undertake testing quickly and efficiently. They will take a thorough approach to identifying any flaws and may even be able to suggest fixes to your developers. They will also know which localization testing tools to use and be able to provide these, thus saving you money on buying them yourself. 


While using professional testers can save you money on localization testing tools, you’ll still need to pay the localization agency for the work that it undertakes. This can be more costly than doing your own research, although I think the difference between cost and value is quite an important distinction here! 

How to Perform a Localization Test

Whether you’re testing in-house or using professional localization services, the test process should follow certain key steps in order to be most effective. 

Build Verification Testing

The first stage of localization testing is build verification testing (BVT). This tests the absolute basic fundamentals of the software or website, so that you know it’s ready for larger-scale testing to take place. The idea is that BVT ensures the site is stable enough for thorough testing to begin. 

Initial Testing Phase

The initial testing phase is a key part of the localization testing process. It looks at the content of the software/website and the user interface. This is the opportunity to begin thoroughly testing every aspect of the product and log any and all defects that crop up during the testing process. 

Analysis and Test Planning

Before beginning the initial testing phase, it’s important to map out your plan for the testing. Paying careful attention to analysis of what’s needed and planning the testing should save you time and effort in the long run. 

Creating Test Cases

As part of the planning process, creating test cases can help to look at how users will interact with the localized website or software. The more closely the test cases can represent the likely interactions of real users, the better. 

Execution of Test Cases

Once the test cases have been mapped out, it’s time to start testing! Each test should be carried out carefully and the results logged. 

Regression Testing

Regression testing occurs when the functional testing process has identified a bug or other defect. The developers then fix that issue before a regression test can take place. The test reviews the progress with fixing the defect while also ensuring that no other aspects of functionality have been affected by the fix. 

Feedback and Report

A localization agency will perform a final round of checks before signing off the software or website for handover to the client. This is the ‘belt and braces’ part of the localization quality assurance process. The feedback will be handed to the client in the form of a report detailing the test results. 

Advanced Localization Testing (Optional)

There are some optional advanced localization tests that you can undertake, should you wish. These include: 

Local User Testing

If you have the time, it can be well worth engaging with a significant number of users in the regions where you plan to launch your new software or website. These users can then test your product and provide feedback, particularly on UI and UX issues. Testing on this scale can be a great way to pick up on issues that relate to a particular region. 

Localized User Testing on Key Demographics

User testing can also home in on specific demographics and thus provide invaluable feedback. User behaviour differs based on a number of factors, such as gender and age. With localized user testing, you can focus on particular demographics and how they experience your product, then shape it in response to their feedback. 


I find that running through the above with a new website or software localization client can really open their eyes to the complexity of delivering a product to a local market. Doing so involves so much more than translation! It’s also key to ensuring a successful outcome when launching the final version in the target region. 

The quality of the agency that you use for your localization testing can make a huge difference to how smoothly the process runs and how effective it is at picking up any defects or bugs that you need to address. As such, be sure you opt for an experienced localization agency with a track record of positive outcomes and an outstanding reputation.  

To sum up my key points:

  • Ensure that you undertake localization testing before launching your website or software in a new region. 

  • Make a strategic decision on whether to undertake the testing in-house or through an agency. 

  • If using a localization agency, be sure to select one with plenty of experience. 

  • Use build verification testing, function testing and regression testing before signing off your software or website as ready for launch. 

  • Include user testing in your approach if you have the time and resources to do so. 

By Ofer Tirosh

Ofer Tirosh is the founder and CEO of Tomedes, a language technology and translation company that supports business growth through a range of innovative localization strategies. He has been helping companies reach their global goals since 2007.



Subscribe to receive all the latest updates from Tomedes.

Post your Comment

I want to receive a notification of new postings under this topic


Need expert language assistance? Inquire now

Do It Yourself

I want a free quote now and I'm ready to order my translations.

Do It For Me

I'd like Tomedes to provide a customized quote based on my specific needs.

Want to be part of our team?