Grammar · Question words
何, what
何 + [particle]
Read なに on its own and なん before counters and です. There is no rule you need to memorise; it follows the sound that is easier to say.
The mistake to avoid
なんで means 'why' in casual speech, but 何で can also mean 'by what means'. Context separates them.
Examples
これは何ですか。
これは なんですか。
What is this?
何を食べますか。
なにを たべますか。
What will you eat?