I learnt that how are you is “genki” or “o genki des ka”, but there is no anata, so how do you know that that’s not “Am I well?”. In other words how do you distinguish 1., 2., and 3. person when no pronoun is written?
As with many things in Japanese (informal language in particular), this is based on context. If you meet someone for the first time in a while, it would make sense to ask them if they are well, rather than asking them if they think you look well.
- Pronouns are often dropped when it is obvious who is being refereed to.
- Unlike many other languages there is no grammatical requirement to include the subject in a sentence.
- You may also choose to omit pronouns if you are unsure which ones are appropriate to address yourself or others, especially as a beginner of Japanese.
In British English, the greeting 'Are you alright?' can be shortened to 'Alright?' and most people can understand from context without specifying a pronoun.