My tongue hath spoken in my mouth - Margin, "palate." The meaning is, that since he had ventured to speak, and had actually commenced, he would utter only that which was worthy to be heard. This is properly the commencement of his argument, for all that he had before said was merely an introduction. The word palate - "in my palate" (בחכי bechêkiy) is used here because of the importance of that organ in the act of speaking. Perhaps also, there may be reference to the fact that the Hebrews made much more use of the lower organs of enunciation - the palate, and the throat, than we do, and much less use of the teeth and lips. Hence, their language was strongly guttural.

Behold, now I have opened my mouth,.... Begun to speak in order to give vent to the fulness of matter within him, which made him, like bottles of new wine, ready to burst; and since he had opened his lips, that he might speak and be refreshed, he desires Job to listen to him, and offers same things to his consideration to induce him to it:
my tongue hath spoken in my mouth: but does not every man's tongue speak in his mouth when he speaks? is there anything singular and peculiar in this, that can excite attention? it may be rendered, "in my palate" (d); which, as it is an instrument of speech, so of tasting and trying food, see Job 6:30; and Elihu's sense is, that he had thoroughly considered what he should say, he had well weighed what he should speak, and should not deliver anything raw, crude, and undigested; he had palated his words, in order to discern whether there was anything in them perverse or not.
(d) "in palato meo", Pagninus, Montanus, Tigurine version, Beza, Schultens; so Mr. Broughton.

ADDRESS TO JOB, AS (Job 32:1-22) TO THE FRIENDS. (Job 33:1-33)
mouth--rather, "palate," whereby the taste discerns. Every man speaks with his mouth, but few, as Elihu, try their words with discrimination first, and only say what is really good (Job 6:30; Job 12:11).
hath spoken--rather, "proceeds to speak."