And after a while - That is, about an hour after (Luke). Peter by this time had returned into the palace or hall, and stood warming himself by the fire, John 18:25.
Thy speech bewrayeth thee - Your language makes it manifest that you are of his company. That is, as Mark adds, he was a "Galilean," and in this way his speech betrayed him. It is probable that the Galileans were distinguished for some peculiarity of pronunciation, perhaps some unique rusticity or coarseness in their manner of speaking, that distinguished them from the refinement of the capital, Jerusalem. This charge, John says John 18:26, was supported by the express affirmation of a kinsman of Malchus, the servant of the high priest, that he had seen him in the garden.

Thy speech - Thy manner of speech, η λαλια σου, that dialect of thine - his accent being different from that of Jerusalem. From various examples given by Lightfoot and Schoettgen, we find that the Galileans had a very corrupt pronunciation, frequently interchanging ת ה א and ע, and so blending or dividing words as to render them unintelligible, or cause them to convey a contrary sense.
Bewrayeth thee - Δηλου σε ποιει, maketh thee manifest, from the Anglo-saxon, to accuse, betray; a word long since lost from our language.

And after a while,.... Mark says, "a little after",
Mark 14:70, and Luke observes, that it was "about the space of one hour after", Luke 22:59, so that here was time to reflect upon what he had been saying, and to guard against another temptation, should he be attacked; but, alas! as yet he was unmindful of his Lord's words, and persists in the denial of him, and that with greater aggravation, than at his first surprise: and indeed his temptation was now more violent: for there
came unto him they that stood by; the officers and servants of the high priest, his attendants that waited upon him, and who stood by the fire, where Peter was warming himself: before he was attacked by single maidservants, now by a body of men, and one of them the kinsman of the man whose ear he had cut off, and who challenged him, as having seen him in the garden: and another confidently affirmed, and swore to it, that he was with Jesus, and was a Galilean; and all of them agreed in this,
and said to Peter, surely thou also art one of them, for thy speech betrayeth thee: not his spiritual speech, for he had not been speaking in the language of a disciple of Christ, like one that had been with Jesus; nor his swearing neither, for this rather showed him to be one of them; but his country language, the brogue of his speech, the Galilean dialect which he spoke: for in Mark it is said, "thou art a Galilean, and thy speech agreeth thereunto", Mark 14:70, for though the same language was spoken in Galilee as at Jerusalem, yet it was not so accurate and polite in Galilee, nor so well pronounced; words of different signification were confounded together. Hence the Talmudists say (b), that "the men of Judah, who were careful of their language, their law was confirmed in their hands; the men of Galilee, who were not careful of their language, their law was not confirmed in their hands--the men of Galilee, who do not attend to language, what is reported of them? a Galilean went and said to them, , they said to him foolish Galilean, "Chamor" is to ride upon, or "Chamar" is to drink, or "Hamar" is for clothing, or "Immar" is for hiding for slaughter.
By which instances it appears, that a Galilean pronounced "Chamor", an ass, and "Chamar", wine, and "Hamar", wool, and "Immar", a lamb, all one, and the same way, without any distinction; so that it was difficult to know which of these he meant. Many other instances of the like kind are given in the same place, which show the Galilean to be a more gross, barbarous, and impolite language, than what was spoken at Jerusalem; and Peter using this dialect, was known to be a Galilean: just as the Ephraimites were known by their pronouncing Shibboleth, Sibboleth,
(b) T. Bab. Erubin, fol. 53. 1, 2. Vid. Buxtorf. Lex. Talmud. in rad,

Thou art one of them; for thy speech bewrayeth thee. Matthew says, "After awhile;" Luke says, "About an hour after." John says that the third charge was made by a kinsman of Malchus, who asserted that he saw Peter in the garden Mark says that they accused him of having a Galilean brogue. As most of the disciples of Jesus were Galileans, this draws attention to Peter. Different districts had their dialects, as in England, or the United States.

Surely thou art also one of them, for thy speech discovereth thee - Malchus might have brought a stronger proof than this. But such is the overruling providence of God, that the world, in the height of their zeal, commonly catch hold of the very weakest of all arguments against the children of God.