Romance languages (Spanish, French, Italian, Portuguese) express modality in the verb through mood morphology. Mood morphology is most common in verbs appearing in subordinate clauses. The semantics of the verb of the main clause or the proposition can determine whether the verb of the subordinate clause takes subjunctive or indicative. For learners whose first language does not have subjunctive mood grammaticalized, acquisition of all the meanings and variable uses of subjunctive in Romance languages is a very difficult task. Chapter 6 discusses studies of second language acquisition showing that the meanings and uses of subjunctive are acquirable with very advanced proficiency. The second part presents instructed intervention studies of the subjunctive in Spanish and other languages that have targeted beginner and intermediate English-speaking learners. The vast majority of the intervention studies on the subjunctive have been conducted to test the effectiveness of the Input Processing approach to language teaching.

Chapter 4 discusses foundational studies linking theoretical findings in second language acquisition and classroom research. The first part of the chapter presents the linguistic background for adverb placement in English and in French within the Principles and Parameters framework of Universal Grammar and then focuses on intervention studies on the acquisition of verb movement and adverb placement in English as a second language by Francophone children in Montreal. The second part of the chapter focuses on question formation in English, the developmental sequences learners of English go through in the acquisition of questions in English, and Pienemann’s Processability Theory, which has been the impetus for important studies on the acquisition of question formation in English as a second language.

Chapter 1 provides an overview of the major topics in linguistics and second language acquisition (SLA) that are particularly relevant for research with second language learners. The first half of Chapter 1 sets out the foundational concepts, and defines such major terms as linguistics, second language acquisition, and heritage speakers. The chapter addresses such influences on language acquisition as age of acquisition and input quantity and quality, comparing and contrasting different types of learner population (monolingual vs. bilingual, first language vs. second language learners vs. heritage speakers). The chapter provides a brief introduction to generative linguistics and generative SLA, discussing evidence for the biological foundations of language and for Universal Grammar. In the second half of Chapter 1, the discussion moves on to the implicit vs. explicit distinction, which is manifested in second language learning, knowledge, and instruction, and which is relevant both to the nature of teaching interventions and to the measurement of learners’ resulting knowledge.

Chapter 3 provides an overview of the English articles the and a(n) in SLA and intervention research. The chapter discusses semantic concepts commonly addressed in SLA studies of articles, including definiteness, specificity, genericity, and kind reference. After a review of relevant SLA experimental studies on the topic, Chapter 3 provides an overview of intervention studies with English articles. The intervention studies are divided into two types: those that focus on particular instructional techniques, such as explicit instruction and different feedback types, and those that take as their starting point theoretical approaches to article semantics. English is the target language in all of the studies discussed, and many of the studies focus on challenges posed by English articles for learners from article-less native languages, including Chinese, Japanese, and Korean.

Chapter 8 focuses on ditransitive verbs, which have a direct and an indirect object. In English, ditransitive verbs participate in the double object construction as well as in a prepositional dative construction. Most second language learners of English, whose language does not have a double object construction, find these structures difficult to acquire. In Spanish, direct and indirect object pronouns are clitics and appear preverbally in certain contexts. Some dative clitic constructions are like the English double object construction. Some direct objects are marked with a preposition in Spanish, which also causes significant difficulty to learners. The first part of the chapter focuses on the acquisition of the double object construction in English and covers foundational intervention studies on this topic. The second part of the chapter turns to the expression of objects in Spanish and presents classroom and lab intervention studies promoting the acquisition of accusative and dative clitic pronouns and of Differential Object Marking in second language learners and heritage speakers.

Chapter 9 addresses intervention study in a variety of phenomena related to word-order configurations that fall beyond the scope of preceding chapters. Four distinct topics are covered: sentence-level word order (canonical word order, such as subject–verb–object in English, vs. noncanonical word order, such as object–verb–subject), adjective ordering (how adjectives are placed with respect to the noun that they modify), relative clauses (clauses which modify nouns), and quantifier scope (the interpretation of ambiguous sentences containing indefinite and universal quantifiers). Within each topic, the chapter provides an overview of the relevant experimental findings from SLA before considering intervention studies on the topic. Chapter 9 has the most diverse representation of target languages in the textbook; the target languages in the intervention studies reviewed include English, German, Spanish, Russian, French, and Japanese.