aliquis (substantive) - aliqui (adjective) ...

[Swth\r]

Is the female form of this pronoun always "aliqua" or only when it is used as adjective? In this case, what is the form of the substantive one?

[adrianus]

Salve Swth\r

In all types of "aliqua", the feminine has only one form in each case. // Casu eodem feminini generis, unam formam habet "aliqua" pronomen utrum relativum an interrogativum an adjectivum and substantivum.

[Swth\r]

Gratiam tibi Adriane!

So the form is always "aliqua"...

Lewis-Short Lexicon says that feminine singular of "aliquis" is rare, but it does not explain the form. And also it doesn't say something about the feminine plural forms...

Oppinaris aliquid, Adriane?

[adrianus]

See A&G §151e on "aliquis", http://community.middlebury.edu/~harris/AG_1.html.
De "aliquis" pronomine, sectionem centum quinquaginta unam sub e litterâ illae grammaticae de A&G vide.

Lewis-Short Lexicon says that feminine singular of "aliquis" is rare, but it does not explain the form.

I think "aliqua" is rare in Latin because "aliquis" masculine can signify "someone" of either sex.
Ut opinor, "aliqua" rarò invenitur, quià plurumquè Latinè "aliquis" pronomen quod verò masculinum est aliquem utrum masculini an feminini generis significare potest.

[Swth\r]

Gratias tibi, Adriane, pro tuo responso ago!

Sed indignatus mihi paulum sum quod tam facilem rem ipse non animadverti. Iam intellexi! Remanebo tamen dum de unusqui(s)que pronomine respondeas mihi in altero loco meo huius eiusdem fori.

Beatus dies tibi sit!