L1 morphs are, in principle, glossed by stem or citation forms of L2 morphemes. However, interlinear morphological glossing crucially revolves around grammatical properties of L1 items. These will differ between L1 and L2. Even if, in certain cases, the L2 stem appearing in a gloss has the same grammatical properties as the L1 morph that it represents, this cannot be expected and therefore not be relied upon. For instance, Latin eum could be glossed by Engl. him, and at the typological level, they do share a number of features. However, eum is accusative and can thus not be indirect object, while him is the form for direct and indirect object. Therefore, grammatical items of L1 are generally not glossed by grammatical items of L2, but by a configuration of symbols taken from the scientific metalanguage and representing their grammatical features, i.e. by grammatical category labels. Thus, Latin eum may be glossed by ‘ANA:ACC.SG.M’.

No bound grammatical or derivational L2 morphemes should appear in glosses. If a free grammatical morph of L1 has no conventional linguistic name, but a close equivalent in L2, the latter may be used as a gloss, as shown in .

However, use of the English words in the second column of the Table is discouraged unless L1 happens to exhibit the same ambiguity as English: