Individual letter pairs that don't begin any roots - tet

 Tet 't ט is the second least used letter in the first two letters of a root. Where did the extra t sound come from? And where has it gone? Was it primal or secondary? Four additional single empty slots in the 401 pages of the concordance involve tet - these are 'ts, 'tq, 'tw, and h't. v't has already been looked at. Tet occurs 6,266 times in the middle of words. But it never occurs in the sequence 'ts or 'tq. 

'tw, however, has 65 uses.

n+w		ni'twh	נטשה abandoned Amos 5:2
l+w		mlu'tw	מלטש honed Psalms 52:4
r+w		iru'twu	ירטשו were dashed to pieces Nahum 3:10
p+w		p'twihon	פטשיהון their tunics Daniel 3:21

And the sequence h't occurs 19 times.

rh+		brh'tim	ברהטים in the girders Song 7:6
lh+		loh'tim	להטים with those who are blazing Psalms 57:5
bh+		bh't	בהט marble Esther 1:6

Single pairs of letters with tet not used in the first two letters of a root. (See also this post.)