Writing papers in language X and translating to English vs. writing papers in English to begin with? I'm working with a group in China, and we were discussing the following question, which I would like to ask here too:


  Question:  Is it better to write a paper in Chinese, then translate it into English, than to write it in English to begin with?


Of course, this question is not limited to Chinese.

Both myself, and the (Chinese) professors in the group I work with felt rather strongly that writing in English to begin with is better.  However, we didn't manage to articulate any tangible reason as to why we feel this way (mostly just out of intuition).  Hopefully the group here can offer some meaningful insight one way or the other.

Note: I'm sure if I leave out the specific context, I'll receive a comment asking for it.  So, in our case, the context was students writing technical scientific research papers (in computer science).
As a non-native English speaker myself, I've faced similar situations during my PhD. Some pros/cons of writing not in English, and then translating. 

Pros: 


If you're working with people who don't speak English very well, it can make it easier for them to write in their native language first, so that they can focus on explaining the idea, rather than trying to find a correct vocabulary. 
You might be able to publish the work twice: once for a Chinese-speaking conference (or journal) and another time in English. 
If you plan to have this paper read by undergraduate students later on, then it might be easier for them to understand it if it's in their native language. 


Cons:


This is a waste of time, since you're basically working on the same thing twice. 
Translating is hard, in general, and speaking two languages does not necessarily make you a good translator. In practice, it might give a structure, but you might have to rewrite entirely each paragraph. 
If you're working with people who aim at staying in academia, they they need to be able to write directly in English. It's hard in the beginning, but it gets much easier with time and practice. 
It could make complicated any external collaboration (I've been collaborating with some people who write their papers in English, but their comments and ideas in another language, it was really frustrating). 
It's probably a subjective perception, but I think that a paper is not only a technical idea, it should also be an interesting piece of work to read. It might be specific to CS (I don't have the same feeling when talking with people in maths), but I feel that we're already reading A LOT of papers (probably due to the multiplication of conferences/journals in CS), and at some point, it becomes harder to focus on those that are not pleasant to read. The best way to make your paper pleasant to read is to think it in English from the beginning. 


Note that in the Cons, I assumed that you would translate the paper yourselves, and that you're not particularly trained for translating technical documents. Of course, that would be quite different if you were to delegate the translation to some professionals.