Where does “daa-chassagh” come from?

daa-chassagh (Manx) comes from Manx daa, from Old Irish dá, from Proto-Celtic dwau, from Proto-Brythonic dọw, from Proto-Celtic *duwo, from Proto-Indo-European dwóh₁ — two.

daa-chassagh (Manx): two-footed, bipedal

Definitions

two-footed, bipedal

Ancestry of “daa-chassagh”, step by step

daa-chassagh traces back through two separate lines of ancestry.

via Manx daa

Step	Language	Word	Meaning
1	Manx	daa	two
2	Old Irish	dá	two
3	Proto-Celtic	dwau	two
4	Proto-Brythonic	dọw	two
5	Proto-Celtic	*duwo	two
6	Proto-Indo-European	dwóh₁	two

via Manx cass

Step	Language	Word	Meaning
1	Manx	cass	foot, leg
2	Old Irish	cos	foot; leg
3	Proto-Celtic	koxsā	leg, foot
4	Proto-Indo-European	koḱs-	joint

Every word from Proto-Indo-European dwóh₁ →Every word from Proto-Celtic *duwo →Every word from Proto-Brythonic dọw →