Asseverative

Further, it is strongly possible that the emphatic or asseverative lamed is etymologically distinct from the preposition, though the Masoretes do not distinguish the two.

A prosthetic 'aleph was added in Hebrew […] and this gave a graphemic distinction between the negative and the asseverative, but the asseverative nevertheless eventually disappeared in Hebrew and other Canaanite dialects.

Delimiting the forms which belong to the asseverative paradigm can be achieved only for some of the forms based on morphological criteria alone.