Translation:I talk with my friend.
So then, it sounds like we're getting into 'indirect object' territory. As with Romance languages, are we talking the cases of speaking with a person, or giving an item to someone, then the person would get the "to" particle in Japanese? (Or if I try to remember my old Latin class, nouns that use the 'dative' case)
と is only used to mean with when used with living things - people/animals. You can tell when it is being used as with and when it is being used as and because if it is being used as and then there would be a list of two or more people or animals eg. ともだちと いもうとは えいが を み に いった けど わたしは こうえん に 行きました - my friend and my younger sister went to watch a movie but I went to the park. Whereas - ともだちと えいが を み に 行った。- I went to watch a movie with a friend.
Prepositions do not in general correspond across languages. Is your claim that there is some 1-to-1 correspondence between the English prepositions and the Japanese particles? I would be flabbergasted, all the more so because I, as a native English speaker, can't tell you precisely what the difference is between "talk with" and "talk to." Sure, "talk to" often sounds more one-sided, but what if I said, "I talk to my friends on week-ends." That doesn't sound one-sided. If anything, it just seems like the emphasis in the sentence is more on the timing than on the activity.
What Chris said. "Speak" and "talk" are entirely interchangeable. Talking with/speaking with someone implies a conversation where more than one person was talking. Talking to/speaking to someone usually implies that the conversation was one-sided (I.e. A teacher giving a lecture or an officer giving commands) and typically comes off sounding a little harder. In some contexts, though, a past-tense "talked to" or "spoke to" could just imply asking someone a question (I.e. "I spoke to them and this is what they said") although, you could also use "with" in this case.
It depends on dialect. I (from Ireland) wouldn't use "talk with", I would use "talk to". I would use both "speak with" (we both spoke to the other) and "speak to" (I definitely spoke, the other person may or may not have spoken). But Americans seem to use "talk with". I only use those words together in "to have a talk (noun) with someone", which usually implies that it was a serious conversation, like, "my son was very rude, I had to have a talk with him to explain how his behaviour was inappropriate".
It is interchangeable, and we dont typically see much difference. You can even say "speak to" and it makes very little difference. The biggest difference id say exists is that saying "speak/talk with" makes me think you will address a group and "to" makes me think you will address a single person
Tachi is a suffix that indicates plural BUT it is rarely used, probably because it sounds very clunky. You would just understand whether it was one friend or more from context. If you wanted to emphasise that it was more than one person or animal then you would add tachi to the end, but it's really not necessary.
Do you mean what is the difference between はなす and はなします. Same verb - different forms. And the します that you see in はなします is not する /します it is just a conjugation of the verb はなす (to speak/talk). はなします is a polite form of the same verb commonly referred to as the ~ます form (masu form).
On some listening exercises, it rejects my answer when I use kanji (like 仕事) and only accepts answers spelled out in kana. For this exercise, I spelled out ともだち and it rejected my answer because I didn't use the kanji. This is very annoying, and the report button doesn't even let me point out that my answer was correct.
This happens all the time with me. Duolingo expects you to use hiragana, and nothing but hiragana, in 9 out of 10 listening exercises, but then something like this pops up without warning and expects the exact opposite. It's impossible to get it "right" on the first try because Duolingo isn't consistent with its rules. I really wish they'd fix this. Getting angry over your daily Japanese isn't a good way to start the day.
Case in point: The next question I got immediately after this one required me to use only hiragana. Argh!
u and i become devoiced (think whispered), and therefore often sound as if they have disappeared entirely, in two cases: a) between two voiceless consonants (p, t, k, s, h, f, sh, ts, ch) and b) at the end of a word, if following a voiceless consonant. (I believe, but I'm not 100 % sure, that for this purpose particles count as part of the word they follow.) However, to make it a little more complicated, there is an exception: if there are two such syllables in a row (examples: shichi, tsuki) only the first gets affected.