This definitely says "virgin". End of discussion for Catholics!
1 [1] Days of Ahaz: who ruled from 735 to 715 B.C. This attack against Jerusalem by the kings of Aram (Syria) and Israel was occasioned by Ahaz' refusal to enter with them into an anti-Assyrian alliance; cf 2 Kings 16.
2 [3] Shear-jashub: this name means "a remnant will return."
3 [6] Son of Tabeel: an adherent of Jerusalem's enemies. His appointment would interrupt the lawful succession from David.
4 [9] Within sixty years and five: if the text is correct, its reference is unknown.
5 [11] Deep . . . sky: an extraordinary or miraculous sign that would prove God's firm will to save the royal house of David from its oppressors.
6 [12] Tempt the LORD: Ahaz expresses in this hypocritical way his preference for depending upon the might of Assyria rather than upon God.
7 [14] The sign proposed by Isaiah was concerned with the preservation of Judah in the midst of distress (cf Isaiah 7:15, 17), but more especially with the fulfillment of God's earlier promise to David (2 Sam 7:12-16) in the coming of Immanuel (meaning, "With us is God") as the ideal king (cf Isaiah 9:5-6; 11:1-5). The Church has always followed St. Matthew in seeing the transcendent fulfillment of this verse in Christ and his Virgin Mother. The prophet need not have known the full force latent in his own words; and some Catholic writers have sought a preliminary and partial fulfillment in the conception and birth of the future King Hezekiah, whose mother, at the time Isaiah spoke, would have been a young, unmarried woman (Hebrew, almah). The Holy Spirit was preparing, however, for another Nativity which alone could fulfill the divinely given terms of Immanuel's mission, and in which the perpetual virginity of the Mother of God was to fulfill also the words of this prophecy in the integral sense intended by the divine Wisdom.
8 [15] Curds and honey: the restricted diet of those who remain after devastation has changed the once fertile fields of Judah into grazing land; cf Isaiah 7:21-25.
9 [20] God will use the Assyrians from across the River (the Euphrates) as his instrument (razor) to inflict disgrace and suffering upon his people.
Only for those who do not wish to consult their own scholars.
Jacob Jensen [O.S.B., S.S.L., S.T.D., Associate Professor, Faculty of Theology, Catholic University of America, Executive Secretary of the Catholic Biblical Association] whose analysis appears in The New Jerome Biblical Commentary [Dust jacket says, "The three editors have all served as president of the Catholic Biblical Association and of the Society of Biblical Literature. They are well-known for their contributions to Catholic and non-Catholic biblical journals."] says of Isaiah 7:14:
The sign now to be given is no longer to persuade Ahaz but will, in the future, confirm the truth of what the prophet has spoken. the young woman: Ha'alma is not the technical term for a virgin (betula). This is best understood as the wife of Ahaz; the child promsed will guarantee the dynasty's future (note again "the house of David" in v 13; cf. v 2) and for this reason can be called Immanual ("with us is G-d"). [Emphasis in original]
And BTW, I do not know what those initials mean in Jensen's brief bio which I copied.
ML/NJ
Therefore the Lord himself shall give you a sign. Behold a virgin shall conceive, and bear a son, and his name shall be called Emmanuel.
It could not be more plain.