The sign to Ahaz is in the next verse: The people will eat yogurt and honey. This is further explained in vv 21-22.

This is to answer Avi Avraham's comment below. I am not allowed to comment, but I can edit my answer: //1. There is not a single scholarly source that translates almah as virgin// " n.f. young woman—pl. עֲלָמוֹת—1. young woman, girl, perh. specif. uninitiated, unknowing female,* David J. A. Clines, ed., The Dictionary of Classical Hebrew (Sheffield, England: Sheffield Academic Press; Sheffield Phoenix Press, 1993–2011), 428." Ernest Klein's "A Comprehensive Etymological Dictionary of the Hebrew Language for English Readers" gives the meaning as "maiden", which means a girl that has never been married.

//2. The shoresh of almah is עלם which means youth, vigor, persistence.// Can you give me an example in the Bible where almah or some derivative word means what you say? Examples of the root word alam meaning hidden are Ps 90:8; Lev 4:13; 5:2-4; Num 5:13; etc.

//3. The sign is not the virgin conceiving, it’s the birth of the child which precedes the victory of Judah in the Syro-Ephraimite War // Yes the sign is not the conceiving. Neither is it the birth of a child. That is no sign. There is nothing miraculous about that. The sign is the miracle that all the people will eat butter and honey.

The sign to Ahaz is in the next verse: The people will eat yogurt and honey. This is further explained in vv 21-22.

1. There is not a single scholarly source that translates almah as virgin

   n.f. young woman—pl. עֲלָמוֹת—1. young woman, girl, perh. specif. uninitiated, unknowing female,* David J. A. Clines, ed., The Dictionary of Classical Hebrew (Sheffield, England: Sheffield Academic Press; Sheffield Phoenix Press, 1993–2011), 428.

   Ernest Klein's "A Comprehensive Etymological Dictionary of the Hebrew Language for English Readers" gives the meaning as "maiden", which means a girl that has never been married.

2. The shoresh of almah is עלם which means youth, vigor, and persistence.
   Can you give me an example in the Bible where almah or some derivative word means what you say? Examples of the root word alam meaning hidden are Ps 90:8; Lev 4:13; 5:2-4; Num 5:13; etc.

3. The sign is not the virgin conceiving, it’s the birth of the child that precedes the victory of Judah in the Syro-Ephraimite War
   Yes, the sign is not conceiving. Neither is it the birth of a child. That is no sign. There is nothing miraculous about that. The sign is the miracle that all the people will eat butter and honey.

almah means virgin. The root of the word means "unknown", which is the Biblical way of saying sexual innocence. It means an innocent young woman. The Hebrew word bethulah, usually translated as virgin, does not mean the same as our English word virgin. Bethulah means a chaste woman who was a virgin before marriage and was faithful to one husband after marriage. It is an honorable term. It is used to refer to a married woman in Joel 1:8; Es 2:17,19; Deu 22:19. If Isa 7:14 had said bethulah instead of almah, it would mean a normal, proper birth.

How could the virgin birth be a sign to Ahaz? It wasn't. The virgin birth is the reason that God will rescue Judah. Because the virgin must give birth to Immanuel, who is God with us, therefore God needs to preserve Judah and the Davidic kingship.

The sign to Ahaz is in the next verse: The people will eat yogurt and honey. This is further explained in vv 21-22.

almah means virgin. The root of the word means "unknown", which is the Biblical way of saying sexual innocence. It means an innocent young woman. The Hebrew word bethulah, usually translated as virgin, does not mean the same as our English word virgin. Bethulah means a chaste woman who was a virgin before marriage and was faithful to one husband after marriage. It is an honorable term. It is used to refer to a married woman in Joel 1:8; Es 2:17,19; Deu 22:19. If Isa 7:14 had said bethulah instead of almah, it would mean a normal, proper birth.

How could the virgin birth be a sign to Ahaz? It wasn't. The virgin birth is the reason that God will rescue Judah. Because the virgin must give birth to Immanuel, who is God with us, therefore God needs to preserve Judah and the Davidic kingship.

The sign to Ahaz is in the next verse: The people will eat yogurt and honey. This is further explained in vv 21-22.

This is to answer Avi Avraham's comment below. I am not allowed to comment, but I can edit my answer: //1. There is not a single scholarly source that translates almah as virgin// " n.f. young woman—pl. עֲלָמוֹת—1. young woman, girl, perh. specif. uninitiated, unknowing female,* David J. A. Clines, ed., The Dictionary of Classical Hebrew (Sheffield, England: Sheffield Academic Press; Sheffield Phoenix Press, 1993–2011), 428." Ernest Klein's "A Comprehensive Etymological Dictionary of the Hebrew Language for English Readers" gives the meaning as "maiden", which means a girl that has never been married.

//2. The shoresh of almah is עלם which means youth, vigor, persistence.// Can you give me an example in the Bible where almah or some derivative word means what you say? Examples of the root word alam meaning hidden are Ps 90:8; Lev 4:13; 5:2-4; Num 5:13; etc.

//3. The sign is not the virgin conceiving, it’s the birth of the child which precedes the victory of Judah in the Syro-Ephraimite War // Yes the sign is not the conceiving. Neither is it the birth of a child. That is no sign. There is nothing miraculous about that. The sign is the miracle that all the people will eat butter and honey.