to have a conversation
Building blocks
Consider this: rääkima - to speak is of Germanic origin (sprechen > spreken > reken = rääkima)
So did Estonians not talk before the arrival of the Germans?
Of course, they did, but they had a different word stem for this: vestma - to speak, to carve.
Because in the old days, a story would be carved.
This also happens to be one of the words old enough to be shared between Finnish, Estonian, and Hungarian.
vest- - speak
-le- - repeatedly (frequentative)
-ma - infinitive ending
Having a conversation is “to speak repeatedly”.
How to use it
Who you are having a conversation with is indicated by the Comitative (ending: -ga, “with”).
What you are having the conversation about is indicated by the Elative (ending: -st, “out of”, “about”).
Examples
Vestlesime vennaga vanadest autodest
Literally: “We talked brother-with old-about cars-about”
Idiomatically: “We had a conversation with [my] brother about old cars”
Vestlesime - Verb - 1P Past Indicative Plural
vennaga - Noun - Comitative Sg, "with brother"
vanadest - Noun - Elative Pl, "about old"
autodest - Noun - Elative Pl, "about cars"
Vestleme kirjutamise teemal
Literally: “We have a conversation of writing on the topic”
Idiomatically: “We have a conversation on the topic of writing”
Vestleme - Verb - 1P Pl Ind Present, "We have a conversation"
kirjutamise - Noun - Genitive Sg, "of writing"
teemal - Noun - Adessive Sg , "on topic"