The verbal system of Proto-Indo-European was primarily based not on distinctions of tense, but rather on distinctions of aspect. The shift from the three aspect system (imperfective, perfective, retrospective) of late Proto-Indo-European to the binary tense system (past vs. non-past) of Germanic explains why the older forms of Germanic lack aspectual forms completely, and also why in historical times the various Germanic languages have developed analytic aspectual patterns of various kinds. In the case of English, these include two perfects to mark past events relevant to the present (I have seen her twice; The warm sea wind was risen and blew over them now), a fully grammaticalised be progressive (She is reading a book) and a second, partly grammaticalised progressive periphrasis formed on a deictic motion verb (Bill went whistling down the street). Also examined in the chapter are changes pertaining to the domain of modality.

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.

This chapter presents the hypothesis that working memory and language evolved in tandem. It reviews the evolutionary origins of each of the components of Baddeley’s working memory model and their role in the evolution of language. The chapter reviews the gradualist position that language did evolve slowly from aurally directed early primate calls and notes that the primary purpose of language has always been communication. The chapter also presents the novel idea that the pragmatics of speech (the purposes of speech) also evolved in tandem with the evolution of working memory. The chapter also reviews the saltationist idea that something happened to language more recent than 100,000 years ago, and that is the release of the fifth pragmatic of speech, the subjunctive mood, which expresses wishes and ideas contrary to fact. The subjunctive mood required fully modern working memory capacity, sufficient phonological storage capacity, and an enhanced visuospatial sketchpad, which are also critically involved in episodic memory recall and simulation. The phenotypic result of this genotype meant that thought experiments could be conducted in a recursive manner. We propose that the fruits of Homo sapiens’s cultural explosion, cave art, creative figurines, and highly ritualized burials, were the direct result of the wishes and imaginings that arise from subjunctive thinking and subjunctive language.

This final chapter summarizes the substantive findings spelled out in the book. These involved historical changes in phonology, including major sound laws and the appearance and disappearance of two new diphthongs, morphology, primarily involving gender, plurality in nouns and pluractionality in verbs, and the origin of the verb grade system, and syntax, focusing on significant tenses, e.g. the falling together of the aorist and the subjunctive, and in the total revamping of the indirect object system. It ends by raising unanswered questions, such as: did Old Hausa have two fully functional contrastive Rs?; could reflexives originally have been built on the word for ‘body’ rather than ‘head’?; how did the current Completive TAM pronoun paradigm come to be used as subjects?; what accounts for the large number of body part terms that begin with /ha/?; and if the current efferential grade incorporates two distinct and unrelated suffixes, what would their original difference in meaning and function have been?