Doth not the ear try words? - The literal meaning of this, which is evidently a proverbial expression, is plain; but about its bearing here there is more difficulty. The literal sense is, that it is the office of the ear to mark the distinction of sounds, and to convey the sense to the soul. But in regard to the exact bearing of this proverb on the case in hand, commentators have not been agreed. Probably the sense is, that there ought to be a diligent attention to the signification of words, and to the meaning of a speaker, as one carefully tastes his food; and Job, perhaps, may be disposed to complain that his friends had not given that attention which they ought to have done to the true design and signification of his remarks. Or it may mean that man is endowed with the faculty of attending to the nature and qualities of objects, and that he ought to exercise that faculty in judging of the lessons which are taught respecting God or his works.
And the mouth - Margin, as in the Hebrew חך chêk - "palate." The word means not merely the palate, but the lower part of the mouth (Gesenius), and is especially used to designate the organ or the seat of taste; Psalm 119:103; Job 6:30.
His meat - Its food - the word "meat" being used in Old English to denote all kinds of food. The sense is, man is endowed with the faculty of distinguishing what is wholesome from what is unwholesome, and he should, in like manner, exercise the faculty which God has given him of distinguishing the true from the false on moral subjects. He should not suppose that all that had been said, or that could be said, must necessarily be true. He should not suppose that merely to string together proverbs, and to utter common-place suggestions, was a mark of true wisdom. He should separate the valuable from the worthless, the true from the false, and the wholesome from the injurious. Job complains that his friends had not done this. They had shown no power of discrimination or selection. They had uttered common place apothegms, and they gathered adages of former times, without any discrimination, and had urged them in their arguments against him, whether pertinent or not. It was by this kind of irrelevant and miscellaneous remark that he felt that he had been mocked by his friends, Job 12:4.

Doth not the ear try words? - All these are common-place sayings. Ye have advanced nothing new; ye have cast no light upon the dispensations of Providence.

Doth not the ear (f) try words? and the mouth taste his meat?
(f) He exhorts them to be wise in judging, and as well to know the right use of their God-given ears, as well as their mouths.

Doth not the ear try words?.... Articulate sounds; and the mind by them judges whether what is expressed and designed by them is right or wrong, true or false, to be received or rejected; so such that have spiritual ears to hear, try the words of God and men, the wholesome words of Christ, and those of false teachers, which eat as a canker; and by their spiritual judgment can distinguish between the one and the other, discern those that differ, and approve those that are excellent, by bringing them to the standard of the word, the balance of the sanctuary, the Scriptures of truth:
and the mouth taste his meat? and judge of it, whether good or bad, or savoury or unsavoury, and so receive or reject it: thus such who have their taste changed, and relish spiritual things, can distinguish between the meat that perishes, and that which endures to everlasting life, even Christ, whose flesh is meat indeed; and those that have tasted that the Lord is gracious, and to whose taste the fruits of Christ and the doctrines of grace are sweet; these will desire the sincere milk of the word, and that strong meat in it, which belongs to discerning and experienced souls; and will feed by faith upon the pure word of the Gospel, and mix it with it, and reject all others. Job by this would signify, that the things his friends had been discoursing of, and which they thought were such deep and wonderful things, were as easy to be searched and found out, tried and judged of, as sounds by the ear, or food by the taste; and it may be also that hereby he suggests, that his doctrine, if it was impartially examined and tried by proper judges, it would appear as plain as anything tried by the ear, or tasted by the mouth. Some think that Job intends by this, that from the senses of hearing and tasting in men might be inferred the omniscience of God, his knowledge of all things, and his quick discernment of men, and their actions, since "he that planted the ear, shall he not hear? he that formed the eye, shall not he see?" Psalm 94:9. Some versions read the whole, "doth not the ear try words, as the mouth tastes his meat" (q)? as in Job 34:3. Saadiah Gaon connects these words "as the ear tries words", &c. with Job 12:12, "so with the ancient is wisdom".
(q) Vatablus, Drusius, Junius et Tremellius, Piscator, Mercerus, Cocceius, Schultens; so Broughton.

As the mouth by tasting meats selects what pleases it, so the ear tries the words of others and retains what is convincing. Each chooses according to his taste. The connection with Job 12:12 is in reference to Bildad's appeal to the "ancients" (Job 8:8). You are right in appealing to them, since "with them was wisdom," &c. But you select such proverbs of theirs as suit your views; so I may borrow from the same such as suit mine.

11 Shall not the ear try sayings,
As the palate tasteth food?
12 Among the ancients is wisdom,
And long life is understanding.
13 With Him is wisdom and strength;
Counsel and understanding are His.
The meaning of Job 12:11 is, that the sayings (מלּין, Job 8:10, comp. Job 5:27) of the ancients are not to be accepted without being proved; the waw in וחך is waw adaequationis, as Job 5:7; Job 11:12, therefore equivalent to quemadmodum; it places together for comparison things that are analogous: The ear, which is used here like αἰθητήριον (Hebrews 5:14), has the task of searching out and testing weighty sayings, as the palate by tasting has to find out delicious and suitable food; this is indicated by לו, the dat. commodi. So far Job recognises the authority of these traditional sayings. At any rate, he adds (Job 12:12): wisdom is to be expected from the hoary-headed, and length of life is understanding, i.e., it accompanies length of life. "Length of days" may thus be taken as the subject (Ewald, Olsh.); but בּ may also, with the old translations and expositors, be carried forward from the preceding clause: ἐν δὲ πολλῷ βίῳ ἐπιστήμη (lxx). We prefer, as the most natural: long life is a school of understanding. But - such is the antithesis in Job 12:13 which belongs to this strophe - the highest possessor of wisdom, as of might, is God. Ewald inserts two self-made couplets before Job 12:12, which in his opinion are required both by the connection and "the structure of the strophe;" we see as little need for this interpolation here as before, Job 6:14. עמּו and לו, which are placed first for the sake of emphasis, manifestly introduce an antithesis; and it is evident from the antithesis, that the One who is placed in contrast to the many men of experience is God. Wisdom is found among the ancients, although their sayings are not to be always implicitly accepted; but wisdom belongs to God as an attribute of His nature, and indeed absolutely, i.e., on every side, and without measure, as the piling up of synonymous expressions implies: חכמה, which perceives the reason of the nature, and the reality of the existence, of things; עצה, which is never perplexed as to the best way of attaining its purpose; תּבוּנה, which can penetrate to the bottom of what is true and false, sound and corrupt (comp. 1-Kings 3:9); and also גּבוּרה, which is able to carry out the plans, purposes, and decisions of this wisdom against all hindrance and opposition.
In the strophe which follows, from his own observation and from traditional knowledge (Job 13:1), Job describes the working of God, as the unsearchably wise and the irresistibly mighty One, both among men and in nature.

Doth not - This may be a preface to his following discourse; whereby he invites them to hear and judge of his words candidly and impartially; that they and he too might agree in disallowing what should appear to be false, and owning of every truth.