How big are groups of people in a specific language?
Agile Practices like scrum typically work around this kind of situation by creating smaller independent modules and sprints. You then form smaller groups of people who are comfortable with a specific language and ask them to work on individual sprints.
So a group of people who are confident with English can work on Module X where else a different team proficient in another language works on Module Y. Both these modules run their independent sprints.
Each team has their own scrum masters (basically a lead or senior developer within that team who knows some level of English can play this role).
Each team has their own daily scrums in the language of their choice. Other team members don’t have to be a part of that scrum since they have scrums in their own languages focused on their specific modules that they attend.
At the end of the day you have a “Scrum of Scrums” – a quick five minute stand up call where these scrum masters / team leads / senior developers (or what ever it is that you want to call them) show up and instead of answering scrum questions like “What did I work on, What am I going to working on tomorrow, and is there something I need from the team?”, answers questions like, “What did we (as in me and my team) work on today, what will we be working on tomorrow and is there something we need from the team?”.
Put simply the local lead, becomes your default interpreter for the rest of the team. This lets these teams work autonomously without a lot of Micromanagement from your side and will also eliminate a lot of friction resulting out of cultural differences. Usually works really well if you have two to three members in each language – which is a perfect size to make pizza teams that can deliver small sprints autonomously.
The leads coming together daily will also ensure that there are no issues with integration. Besides you can use continuous integration to ensure that what each team is building fits in the larger image. Standard XP practices will help you with that.