One 'l' /ell/ or two? This is important not only for correct spelling (pravopis), but also for appropriate pronunciation - I mean the pronunciation which expresses the right meaning of the word. To file a document is pronounced /fájl/, so the system of filing must be /FÁJ-ling/, so the spelling must be with only one 'l'. With double 'll' (filling) it would be pronounced /FI-ling/, and that means "plnka" or "plnenie".

Full means "plný/á/é" and fully is "plne", but to fulfill (the first 'l' is single, the second is double, also in fulfilling and fulfilled) means "splniť" (also "splnenie" and "splnený/á/é"), and the pronunciation is /ful-FIL/ or even /fl-FIL/. Other words with double 'll' in the extracts are million, pronounced /MILjn/ and metallurgy, pronounced /MEtl-édži/. Only metallic is pronounced /mi-Talik/.