NoSMark: The function S is not explicitly marked, while P, A, or both are marked. S is therefore marked with a zero (∅) morpheme.
(1) laura énekel.
Laura sing-prs.3sg
‘Laura is singing.’
(2) laura level-et ír.
Laura letter-acc write-prs.3sg
‘Laura is writing a letter.’
In Hungarian, if the S (1) or the A (2) is presented by a noun, they are unmarked, while the P takes the accusative suffix (2). From a formal perspective, the grammatical subject (S/A) is identifiable by its nominative case marking and the agreement of verbal suffix (cf. Tolcsvai Nagy 2012, 2013: 283‒312, É. Kiss 2002: 8‒14).