I will answer the second question. The verbs, "speak" and "talk" are translated into Japanese as "hanasu" (話す) basically. For example, "I speak to you" is translated "私はあなたに話す"
Japanese verbs conjugate. For example, "話す" has five conjugations.
話さ "hanasa"
話し "hanasi"
話す "hanasu" (this is basic)
話せ "hanase"
話そ "hanaso"
By the way, we Japanese add some meaning to verb by adding jyodoshi (助動詞) and/or "jyoshi" (助詞).
For example, "reru" (れる) and "reta" (れた) make the verb a passive verb.
"Kare ni hanasa-reta kotoba" (彼に話された言葉) = Word spoken by him
"Seru" (せる) makes the verb a causative verb.
"Kare ni hanasa-seru" (彼に話させる) = "I make (have/ let) him speak."
Both "tara" (たら) and "ba" (ば) mean "if."
"Watashi ga hanashi-tara" (私が話したら) and "Watashi ga hanase-ba" (私が話せば) = "If I speak"
"U" (う) means intention to do or "let's."
"Watashi to hanaso-u" (私と話そう) = "Let's talk with me"
"Watashi ga sore ni tsuite hanaso-u" (私が話そう) ="I will talk"
"Darou" (だろう) means "probably."
"Kare ga hanasu-darou" (彼が話すだろう) = "He will probably talk."
The combination of "jyodoshi" (助動詞) and/or "jyoshi" (助詞) and conjugating of verb has some principles. However, it is difficult for me to explain about all principals methodically. I think my explanation technically, but I hope this helps your understanding little a bit
