In my experience, the main difference is that people not comfortable with English will spend more time on naming things and code reviews. But it tends to get be

In my experience, the main difference is that people not comfortable with English will spend more time on naming things and code reviews. But it tends to get better with experience. Companies with a poor engineering culture often name things in their own language, which makes an awkward and confusing mix because everything else is in English. I have noticed interesting regional differences too. In France it is hard to get people to use English, but otherwise the grammar is mostly fine. But in Asia it's easy to get people to use English, but it's not easy to get the grammar right. For example they have a hard time with plurals when naming variables. Of course it's just my data point and a broad generalization, because there are also very skilled developers everywhere.