Only "my friends suggested that I talk to him" is correct. "To suggest" is one of the verbs that govern the subjunctive. Other verbs govern the base form, the infinitive, or the gerund. Some verbs allow more than one option, with or without a change in meaning. I'm afraid that you'll just need to learn and practice every verb individually (except that prepositional verbs always govern the gerund).

"My friends suggested that I talk to him" is correct, the rest are not. The first one is understandable colloquially but is grammatically incorrect. Hope this helps :)

Hi Tuvya, The best answer would be: "My friends suggested to me that I talk with him" Although in this sentence "me" is an indirect form, it normally takes the preposition 'to'. Simply adding 'to' before 'me' in the first sentence would also make it usable... albeit a bit clumsy. Also, in most cases, we talk 'with' somebody. In the cases where we would talk 'to' somebody, it would imply we are giving information or are providing some kind of service. Generally when we are sharing information with a third party, we 'talk with them'. Hope this helps.

Actually the other one “my friend suggested me that I talk to him”. is not exactly correct. You can say “My friend suggested to me that I talk to him.” Never say “my friend suggested me…” Always use “to” with “me”: “suggested to me”. You should always use “to me” or “that I”… “My friend suggested to me that I should…” “My friend suggested that I should…” You can say it in a relaxed way: “My friend suggested, I should…”

It depends on the context. The first sentence isn't ideal but it might be said if your friends decided that someone needed to talk to him and that you were the best person to do it.