После разговора с другом мне стало ещё спокойнее.

Because после always takes the genitive case.

• разговор = conversation, talk
• после разговора = after the conversation / after talking

So разговор changes to разговора because it is governed by после.

This is a very common pattern in Russian:

• после урока = after the lesson
• после работы = after work
• после фильма = after the film

Here с means with, and in that meaning it normally takes the instrumental case.

• друг = friend
• с другом = with a friend / with my friend

So the form другом is instrumental singular.

Be careful: с can also mean from/off, and then it may take a different case. But in this sentence it clearly means with, so instrumental is used.

Russian often uses the dative case for the person who experiences a feeling or state.

So:

• мне literally means to me
• мне стало спокойнее literally means something like it became calmer to me

That sounds strange in English, but it is very natural in Russian.

This pattern is common:

• мне холодно = I am cold
• ему скучно = he is bored
• нам стало весело = we started feeling cheerful

So мне is not the subject here. It marks the experiencer.

Стало is the past tense, neuter singular form of стать.

In this sentence, стать means to become:

• стало спокойнее = became calmer

Russian often uses the neuter singular past tense in impersonal constructions, where there is no normal subject.

So even though English says I became calmer, Russian expresses it more like:

• to me it became calmer

That is why you see стало, not стал or стала.

Because this is an impersonal construction.

Russian does not always need a subject like English does. In sentences about physical or emotional states, it is very common to say:

• мне стало легче = I felt better
• ему стало страшно = he became frightened
• нам стало ясно = it became clear to us

So in мне стало ещё спокойнее, the focus is on the change of state, not on a grammatical subject.

In this sentence, спокойнее is the comparative form meaning calmer / more calm.

It comes from спокойный / спокойно.

In this kind of impersonal sentence, Russian often uses a comparative state word:

• лучше = better
• хуже = worse
• легче = easier / lighter
• спокойнее = calmer

So мне стало спокойнее means I felt calmer or I became calmer.

You do not need to force it into one neat English category. In Russian grammar, this type of word often behaves like a comparative predicate in a sentence about a state.

Here ещё means even or still more.

So:

• стало спокойнее = became calmer
• стало ещё спокойнее = became even calmer / calmer still

It adds the idea that the speaker was already somewhat calm, and after the conversation the feeling increased.

Because the sentence talks about a change in degree.

• мне спокойно = I feel calm
• мне стало спокойно = I became calm / I started feeling calm
• мне стало спокойнее = I became calmer

The comparative shows that the speaker’s state improved relative to how they felt before.

Yes, but спокойнее is more natural here.

Russian often prefers the simple comparative:

• спокойнее rather than более спокойно

Более спокойно is grammatical, but it usually sounds more formal, analytical, or less idiomatic in a simple everyday sentence.

So мне стало ещё спокойнее is the most natural version.

It can express either idea, depending on context.

• разговор с другом literally = conversation with a friend
• после разговора с другом = after a conversation with a friend / after talking with a friend

In natural English, both can work. Russian uses the noun разговор here, where English might prefer either a noun phrase or a verbal phrase.

Yes, the word order can be changed, because Russian word order is relatively flexible.

This version starts with После разговора с другом, which sets the scene first:

• After the conversation with my friend, I felt even calmer.

Other orders are possible, for example:

• Мне стало ещё спокойнее после разговора с другом.

That version puts the emotional result first and the time/cause phrase later.

So the original word order is natural, and it emphasizes what happened after that conversation.

By itself, с другом literally means with a friend.

But in many contexts, English naturally translates this as with my friend if the speaker clearly has a specific friend in mind.

Russian often leaves possession unstated when it is obvious from context. So:

• с другом can mean with a friend
• and in context, it may be understood as with my friend

A very literal breakdown would be:

• После = after
• разговора = conversation
• с другом = with a friend
• мне = to me
• стало = it became
• ещё = even
• спокойнее = calmer

So, very literally: After the conversation with a friend, it became even calmer to me.

That is not good English, but it helps show how the Russian grammar works. A natural English translation would be: After talking with my friend, I felt even calmer.