It is, perhaps, a statement of the obvious, but before you start developing, ensure that you fully understand the problem you have been asked to solve. The standard journalist's questions are a good framework to aid your understanding. Consider the following:
- Who: Will the two languages be displayed to all users or only to certain users? In our case, all users.
- What: Are we talking about US English or UK English? Does the client want "Mandarin", which means mainland Chinese displayed using the simplified character set? Our client has specified UK English and simplified Chinese Mandarin.
- Why: Is this because our users are bilingual, or is this being included as a teaching aid? The client is wanting two languages ...