The string of his tongue was loosed - The difficulty in his speaking was removed.

He spake plain - Ορθως, distinctly, without stammering. One MS. has, And he spoke, praising God. There is no doubt of this: but the evangelist, I think, did not write these words.

And straightway his ears were opened,.... It is in the Greek text, "his hearings"; the instruments of his hearing, and so rightly rendered, "his ears": the Persic version reads, "both his ears"; but the word "both" is unnecessary, since the word, "ears", takes in both. Such a power went along with the words of Christ, when he said, "be opened"; that immediately, as soon as ever the words were pronounced, the man's hearing came to him, and he heard as quick as ever he did before he lost it, or, as any other man:
and the string of his tongue; which caused it to cleave to his jaws, or the roof of his mouth, and hindered him from speaking plainly,
was loosed, and he spake plain; "easily", as the Syriac version renders it; without any difficulty to himself, and so as to be readily understood by others. Thus those whose ears are opened, and whose tongues are loosed in a spiritual manner by Christ, speak plainly of what they have heard and seen, and felt; they can give a plain and clear account of the work of God upon their souls; how they have been convinced of the impurity of their nature, the corruptions of their hearts, and the exceeding sinfulness of sin, in heart, lip, and life; how they have seen Christ to be an all sufficient and suitable Saviour, and have been directed, and encouraged, to go to him, for healing, pardon, righteousness, and everlasting salvation; they can tell what promises have been applied to them, and what comforts they have enjoyed; how busy Satan has been with them; and what temptations of his they have been delivered out of, and by what means: in a word, they can speak plainly of the love of God to them; of the glories and excellencies of Christ; of their faith and hope in him, and love to him; and of the operations of the Spirit of God upon their hearts; and of the glories of the world to come, they are in the expectation of, so far as they are taught of God.

And straightway his ears were opened--This is mentioned first as the source of the other derangement.
and the string of his tongue was loosed, and he spake plain--The cure was thus alike instantaneous and perfect.

His ears were opened. At once both his difficulties were removed.