Chapter 5 discusses SLA and intervention studies with inflectional morphemes, functional elements that mark such grammatical distinctions as tense, subject–verb agreement, and grammatical gender. Inflectional morphology is known to present a challenge to learners and has been the subject of multiple intervention studies. Chapter 5 begins with an overview about the debate in SLA concerning whether learners’ difficulties with inflectional morphology reflect underlying syntactic impairments or more surface problems. The chapter then reviews intervention studies on tense marking that use processing instruction, intervention studies on verbal morphology that use more explicit vs. more implicit instructional approaches, and intervention studies on grammatical gender that vary the types of feedback that learners receive. The target languages of the intervention studies include both English and several Romance languages (Spanish, Italian, and French).

The chapter gives an overview of the possible positions of finite verbs across the Germanic languages. These possibilities are shown to depend on three independent choices related to three different parts of the clause, CP, TP, and VP:

1. (1) If the language is a verb second (V2) language, the finite verb in every main clause moves to C°.

2. (2) If the language has V°-to-T° movement, the finite verb in every clause moves to T° (but if the clause is a V2 clause, then the finite verb will move on from T° to C°).

3. (3) Finally, depending on whether a language is verb-object (VO) or object-verb (OV), the finite verb in every clause will occur either preceding or following all other elements inside VP, e.g., objects, other complements, adverbials (provided the verb has not undergone movement to T° or to C°).