Speak：後壹般加語言名稱，如He can speak Chinese.
talk:交談，如：He often talks with me during lunchtime.此時talk也可改為chat（閑談）
call：壹般用於打電話中，如：He will call me later.
tell:告訴，如：He is talling me an interesting story.
另附上字典中的解釋
Say
1.說，講；表達；表明，宣示；聲明，主張，斷定。 all you know and say it without reserve. 知無不言，言無不盡。 S- no more. 別再說了。 Never say die! 不可氣餒! Do you mean what you say? 妳是說真的嗎？ 妳說的是當真的嗎？ I mean what I say. 我說了是算數的。 S- what you mean. 把妳的意思說明白。 Do you say so 那是真的嗎？ You don't say (so)! 未必吧!不至於吧!真的! You may well say so. 妳那樣說可能(固然)對；妳不妨那麽說。 Who shall I say, sir (傳達者問來客)妳是哪壹位？ 請問尊姓？ I'll say so. 〔美俚〕妳說得很對；我也同意。 He said “Yes”.＝ “Yes,” said he. 他說“是”。
2.背誦，背，念，誦讀。 to be said or sung 供誦讀或歌唱。 say one's lessons 背功課，背書。
3.〔祈使句〕假定(說)，比如說，就說，姑且說，大約 (＝let us say )。 a few of them, say a dozen 其中幾個人，假定[比如說]壹打左右吧。 a couple of hours, say from four to six 兩個鐘頭的時間，比方說從四點到六點。
4.〔美口〕＝ I say 〔見下〕。
5.〔俚語〕反駁。
as much as to say 等於說；好像是說…壹樣地；像要說…似地。 as to say 〔插入語〕也就是說。 Easier said than done. 〔諺語〕說著容易做時難。 have nothing to say for oneself 〔口語〕總是不開口；沒話可說，壹言不發。 have something to say for oneself 有要辯白的話。 have something [nothing] to say to [with] 要〔不〕對[和]…爭辯，有話要說[沒話可說]，有[沒有]關系。 hear say 聽說，據說。 I cannot say . 我不知道。 I cannot say much for .... 對…不以為…怎樣好；對…不敢恭維。 I dare say 〔插入語〕大概；許是，我想。 I say＝〔美口〕；餵；餵餵；哎呀；我是說…〔加強語氣〕；哎呀 ( I say, John＝〔美國〕say， John 餵，約翰。 I say, what a beauty! 哎呀!好漂亮的人[東西])! I should say (that) 大概，許是。 I should say not 我以為不是那樣。 (It) goes without saying that 當然不用說…。 It is said that .... 據說，聽說。 (let us) say 比如說；大約。 may well say that …很可以說。 mean what one says 是當真的。 No sooner said than done. 壹說就做；說到做到。 not to say ...，雖不能說…，即使不說 ( It is warm, not to say hot. 雖說不上熱，但也很暖和了)。 say a good word for 替…說好話，替…說情，替…辯護，推獎。 S- away! 完全說出來吧；盡量說吧! say for oneself 分辯，爭辯。 S- on. 說下去，繼續說吧。 say nay 否認；拒絕。 say one's prayers 禱告。 say one's say [word] 說出自己的想法；把話說完；暢所欲言。 say out 坦白說出，直說。 say over [again] 1. 再說，反復說。 2. 背誦…。 say something ＝saygrace 飯前後的禱告；即席演說幾句。 say something of 批評。 say the word (下)命令。 say to do 〔美俚、英卑〕叫，命 (He said (for me) to tell you not to come. 他叫(我)告訴妳不要來。 They said to telephone. 他們叫(我)打電話)。 say (sth.) to oneself 暗自思量，心想，心中盤算。 ★“自言自語”是 talk to oneself. so to say 〔插入語〕 1. 好比，活像是，恰如，正像。 2. 可以這麽說。 That is saying a great deal. 這可了不得。 that is (to ) say 〔插入語〕即，換句話說，(也)就是說；至少。 They say ... 據說，聽說。 There is no saying .... 很難說，說不準。 though I say it (who should not) 雖然不應該由我來說；我來說雖然不太好。 to say nothing of 〔插入語〕更不用說，更不待言，更不必說。 to say the least of it 至少〔插入語〕可以(這樣)說；退壹步說。 What do you say to (a walk)? ＝What say you to (a walk)? (去散散步)妳說怎麽樣[以為怎麽樣]？ (散步)好不好？ What I say is .... 我的意思是…。 when all is said (and done) 結果；畢竟。