The Moin dictionary, one of the most trusted dictionaries of Farsi, has written "Sapõn" (if I'm doing the accent right) as a non-Arabic form of the word صابون /saabun/, and this can be traced to Latin sāpō, soap. According to Wiktionary:
From Proto-Germanic saipǭ, from Proto-Indo-European seyb-, *seyp- (“to pour out, trickle, strain”). Cognate with Old English sāpe (“soap, salve”), Old English sāp (“amber, resin, pomade, unguent”), Latin sēbum (“tallow, grease”). More at soap.
It's from French, the 'Lingua Franca' Both Farsi and Swahili got it from French ultimately, which is derived from Latin
btw French soap is savon (the v used to be p/b)
According to the Wiktionary, "sabuni" comes from Arabic "صَابُون" (ṣābūn), from Latin "sāpō". Other descendants from the Arabic "sābūn" are Hindi "साबुन" (sābun), Malay "sabun" and Turkish "sabun".
That's unheard of. Also you seem to misunderstand what lingua franca is. It's a type of languages that are used by speakers of different languages. French can act that way, but that has nothing to do with Swahili.
I think it's valid, just not accepted yet because they're working out the bugs in beta, so make sure to report it if it happens to you again.
Why wouldn't it be Ninaosha? I see Anaosha all the time. Would Ninaosha work in this instance?
Also, does the word Anafua also exist?
Because the verb -osha is for washing other things (usually the dishes).
The verb -fua is for washing clothes. Then there is -nawa for washing parts of the body.
These verbs are conjugated in the standard way, including "ninafua (nguo)" = I wash (clothes) and "anafua (nguo)" = he/she washes (clothes).
You can look up "wash" here: