How to Improve Your Internationalization Speed: An Interview with Lang Co-founders Eric Yu and Peter Zhou

Eric Yu and Peter Zhou are the co-founders of Lang, a YCombinator startup focused on simplifying internationalization. With combined experience from Facebook, Instagram, and Atrium, Eric and Peter’s developer-focused approach aims to make internationalization possible for businesses of all sizes.

Our discussion explored the major pain points that Eric and Peter experienced in their previous internationalization work, before diving into the technology that Lang is building to achieve their mission. For more expert insight into the world of localization, check out the rest of our interview series here.

Gengo: How did you become involved in the internationalization business?

Eric: Before we started Lang, Peter and I had both worked closely with Facebook’s internationalization infrastructure. Although Facebook streamlined the experience for developers, it was still painful to manage your own translations and wait for them to be completed before releasing features. Later, we met Abhi, who built the internationalization stack from scratch for his old company. We bonded over our shared pain points, and decided to make something better!

G: Where did the idea for Lang come from and which common localization problems does your software primarily try to solve?

Peter: We believe engineering cost is one of the biggest pain points when localizing an app. Anyone who has re-engineered their codebase to support multiple languages probably understands that the process is very time-consuming.


There are many solutions to source translations quickly, but no developer-focused tool to streamline and automate the process end-to-end.


We built Lang to turn a months-long process into a 30-minute one. We’re working on getting companies translated as fast as possible with minimal developer time, but we’re tackling an even bigger problem. The biggest problem with internationalization is the tax on developer speed that ensues after launching in other countries. Developers now need to wait for translations, perform multiple stages of QA, and handle data differently. We’re handling one piece of the problem right now, but ultimately want to alleviate all the pain points.

G: How does Lang work, and which platforms do you currently support?

E: The core of Lang is the command-line interface (CLI). Using our CLI, developers can manage, request, and receive translations by entering one line into their terminal. All devs need to do is mark the phrases in their code that they want to translate with a special function called “tr.” Under the hood, we find all the “tr” marks in their code, automatically request new translations, and pull in the completed translations from our human translators. Larger companies spend months building this infrastructure and integrating with translation services. Currently we only support JavaScript-based apps, but we want to bring this to everybody.

G: You’ve chosen to integrate with Gengo to provide the human translation behind Lang’s software. What were your reasons for doing this and how will this decision benefit your customers?

P: After looking at all the available translation services, Gengo was by far the simplest and easiest service to integrate with. We could tell the Gengo team spent a ton of time thinking about the developer experience, and, as a dev tool ourselves, we couldn’t think of a better service to work with.

For our customers, this means human translations delivered in half the average market turnaround time, and the best possible pricing so our customers can focus on launching and not finance.

G: There are a huge range of tools that aim to help businesses with their localization needs. How does Lang differ from its competitors, and which new ideas do you bring to the table that excite you the most?

E: Lang is the first localization tool that prioritizes reducing engineering overhead. Our onboarding gets any team set up in 30 minutes, and then the workflow fits seamlessly into any startup’s process.


We’re most excited about unlocking the startup market, and getting smaller companies to international users earlier and faster.


We think of ourselves as the Stripe for internationalization. Ultimately, we want to change the industry’s behavior towards internationalization. Currently, people see it as a huge risk, resulting in either massive growth or tremendous cost to their business. We see it as a cheap, natural benefit for every company. In the future, it should be a bug to have an app only available in English.

G: What further capabilities do you plan to add to your software?

P: We’re thinking of two major features at the moment. Currently we only translate texts stored in the codebase, but our customers want us to translate the dynamic content that their users create. This is a huge problem, and we’re excited to dive deeper into it.

In addition, one of the most common problems for developers after translating an app is the layout being broken. German words are far longer than English ones, and many companies completely redesign their apps so they beautifully support both languages. This is another tough challenge to fix, but we’re taking our first steps to help customers address these problems.

G: More generally, how do you see the localization space developing in the future?

P: The emerging market is massive. It’s growing quickly. The English-speaking Internet is saturated, and demand for translation services and tooling will only increase in the future. We’re excited about AI further decreasing translation costs so that more people can have access to cheap, quality translations. The world will become more connected, and we’re excited to help people across all ethnicities, borders, and differences communicate better.

G: Finally, do you have any advice for anyone looking to internationalize their app or website?

E: Take into account your developer’s time! Internationalization looks like a simple process at first, but it takes a lot of time to set up properly. Also, we’ve learned that the real cost of internationalization comes after you’ve translated everything. Maintaining a multilingual app requires QA, tests, and continuous localization. It’s a huge tax on developers, preventing them from shipping features quickly. If you want to know how Lang can help, just shoot me an email at!

Daniel Smith

The author

Daniel Smith

Daniel writes a variety of content for Gengo’s website as part of the marketing team. Born and raised in the UK, he first came to Japan by chance in 2013 and is continually surprised that no one has thrown him out yet. Outside of Gengo, he loves to travel, take photos and listen to music that his neighbors really, really hate.

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