As-salaamu 'alaikum wa rahmatullaah wa barakaatuh. I know that the one who abandons salaah falls into major kufr, but what about if someone abandons salaah and doesn't know how to pray properly? And he doesn't try to learn the salaah either? Is he still to be considered a kaafir? Jazaakumullaahu khair.
It is never permissible for a Muslim to abandon the Salah, in fact, it is obligatory on them to perform the Salah any way they can, according to their circumstances. But they must try to learn it and have Taqwa (fear Allah as He should be feared) with regard to this.
[url=http://www.alifta.org/Fatawa/FatawaChapters.aspx?View=Page&PageID=2143&PageNo=1&BookID=7]Performing Salah in non-Arabic language [/url]