Somebody wants to do something

[TexMurphy01]

Hi there.

I understand how to say I want to do something, or that I want something (tai verb ending or hoshii). What I'm not sure about is how to say, firstly, if someone else wants to do something and, secondly, something like 'if you (that term meaning a person in general, not 'you' specifically) wanted to do something, (something something)...'

The second of those I guess isn't that clear, so I'll provide an example: if you (one) wanted to talk to your friends, a mobile phone would be useful.

So if someone can help me out with this, that would be great.

Thanks in advance.

 

[Toritoribe]

The -tai form can't be used for second or third person in declarative sentences, since we can't know others' feelings/emotions. ～がる, らしい, そうだ, ようだ, or like that (guess, seems like, heard,,,) is used instead.
e.g.
聞きたがっている
聞きたいらしい
聞きたそうだ
聞きたいそうだ
聞きたいようだ


たい/ほしい can be used for "you" as "one".

友達[Tomodachi]と話[hana]したいなら、携帯[keitai]が便利[benri]です。。