Based on PE/17, I’ve always thought that S -g is the informal (familiar) 2nd p. sg. verbal suffix, while -dh is the formal (polite) 2nd p. sg. verbal suffix, the latter of which was replaced by -l by Quenya influence (cf. the verb linnathol in PE/22:167 and the pronoun change de, dhe >> le in PE/17:26). In the conjugation chart presented in VT/50:22, however, +Carl Hostetter considers cerig the polite form, while cerith (the precursor of ceridh, I suppose) the familiar form.
Now, what is the truth?
Ekin Gören Dec 05, 2015 (18:44)
Ni & -n 1st
Ci/gi & -g 2nd fam.
Le & -l 2nd form.
De/dhe & -dh 2nd sg. Doriath form.
Te/de & ?? 3rd [-d poss. only?]
plurals:
Me/ve & -f 1st exc
Pe/be & -b inc
De/dhe & -dh 2nd plural
Ti/di? & ?? 3rd [-r verb only?]
Александр Запрягаев Dec 05, 2015 (18:51)
Sg.
1 -n
2fam. -g
2form. -l
3 X
Pl.
1excl. -f
1incl. -b
2 -dh
3 -r
However, this cannot be the case when speaking about dialects especially Doriath; based on the PE17 table, I venture for that:
Sg.
1 -n
2fam. -g
2form. -dh
3 X
Dl.
1excl. -vid
1incl. -bid
2 -dhid
3 -d
Pl.
1excl. -f
1incl. -b
2 -dh(ir)
3 -r
Lőrinczi Gábor Dec 05, 2015 (21:44)
Lőrinczi Gábor Dec 05, 2015 (21:50)
Ekin Gören Dec 05, 2015 (22:08)
Tamas Ferencz Dec 06, 2015 (11:03)
Paul Strack Dec 07, 2015 (04:11)
Maybe, though Tolkien imagined some kind of semantic shift where the familiar became formal. English "thee" was originally familiar, but after it fell out of common use, many modern English speakers see it as formal due to its use in older texts, particularly the Bible and Shakespeare.