PS: Don't the verses which say it has been made clear mean "It is revealed using clear Arabic words" rather than that the meaning is clear?
I believe the Koran mentioned twice that it is revealed in Arabic:
Sura 16:
103 And We know well that they say: Only a man teacheth him. The speech of him at whom they falsely hint is outlandish, and this is clear Arabic speech.
Sura 26:
192 And lo! it is a revelation of the Lord of the Worlds,
193 Which the True Spirit hath brought down
194 Upon thy heart, that thou mayst be (one) of the warners,
195 In plain Arabic speech.
UPDATE
Hmmm, my memory seems to be gone; just checked
http://corpus.quran.com/ and found all these references in addition to above:
ʿarabiyyan (عَرَبِيًّا) adjective (
accusative masculine singular indefinite adjective (صفة منصوبة)
(12:2:4) ... (as) a Quran in Arabic ...
(13:37:4) ... (in) Arabic. ...
(20:113:4) ... (in) Arabic ...
(39:28:2) ... (in) Arabic ...
(41:3:5) ... (in) Arabic ...
(42:7:5) ... (in) Arabic, ...
(43:3:4) ... (in) Arabic ...
(46:12:11) ... Arabic ...