PS

*ˀil- - god (Fronzaroli 1965b:248, 262, 267; Kogan 2015: 179)

PCS
*ˀilāh- - god (Kogan 2015: 179)

The origin of the -āh extension cannot be established with certainty, but as plausibly argued in Huehnergard 2005 (following Brockelmann 1908:334; cf. Pardee 1999:286, 2000:36), it may represent a back-formation from the plural *ˀil-āh-ūma

Akkadian
ilu - god (CAD I 91, AHw. 373)
Hebrew
ˀēl - god (HALOT 48)
Mehri
ˀāl - god (Lonnet 2005:206)
Jibbali
ˀɔ̄ẑ - god (JL 3)
Alternatively < PS *baˁl- ‘lord,’ cf. the by-forms ˀɔˁẑ, ˀɔ̄ˁẑ, ˀɔ́ˁɔẑ in JL 22, as well Mhr. abɛli ‘God’ (ML 41).