Discussion of Indo-European origins and dispersal focuses on two hypotheses. Qualitative evidence from reconstructed vocabulary and correlations with archaeological data suggest that Indo-European languages originated in the Pontic-Caspian steppe and spread together with cultural innovations associated with pastoralism, beginning c. 6500-5500 bp. An alternative hypothesis, according to which Indo-European languages spread with the diffusion of farming from Anatolia, beginning c. 9500-8000 bp, is supported by statistical phylogenetic and phylogeographic analyses of lexical traits. The time and place of the Indo-European ancestor language therefore remain disputed. Here we present a phylogenetic analysis in which ancestry constraints permit more accurate inference of rates of change, based on observed changes between ancient or medieval languages and their modern descendants, and we show that the result strongly supports the steppe hypothesis. Positing ancestry constraints also reveals that homoplasy is common in lexical traits, contrary to the assumptions of previous work. We show that lexical traits undergo recurrent evolution due to recurring patterns of semantic and morphological change.

Morphological strategies for inflectional exponence have traditionally been associated with different stages in the evolution of languages. Moreover, the so-called MORPHOLOGICAL CYCLE (or the TYPOLOGICAL CYCLE inmorphology) is claimed to involve a unidirectional sequence of changes that leads from isolation to agglutination (separative exponence in inflection) and subsequently to fusion (cumulative exponence). But this rigid schema happens to exclude a wealth of diachronic developments that are solidly attested in the history of various languages: the shift from cumulative toward separative exponence perhaps constitutes the strongest challenge to the unidirectionality hypothesis implied by the classic typological cycle. Here I survey the data illustrating agglutinative developments inside fusional systems, a task that first requires a canonical definition of morphological techniques. Then the mechanisms underlying this significant typological change are classified and analyzed in detail. The final part of the article is devoted to discussing the possible causes behind the reversal of the morphological cycle. The diachronic evidence at our disposal points to a rather clear differentiation between the language-internal causes that seem to determine the shift from agglutinative to fusional structures and the language-external causes (contact influence of a particular kind) that commonly lie behind the reverse morphological change.

Natural human languages often contain variation (sociolinguistic or Labovian variation) that is passed from one generation of speakers to the next, but studies of acquisition have largely ignored this, instead focusing on aspects of language that are more deterministic. Theories of acquisition, however, must be able to account for both. This article examines variation from the perspective of the statistical learning framework and explores features of variation that contribute to learnability. In particular, it explores whether conditioning variables (i.e. where the pattern of variation is slightly different in different contexts) lead to better learning of variation as compared to when there are no conditioning variables, despite the former being conceptually more difficult. Data from two experiments show that adult learners are fairly good at learning patterns of both conditioned and unconditioned variation, the latter result replicating earlier studies. Five-to-seven-year-old children, in contrast, had different learning outcomes for conditioned versus unconditioned variation, with fewer children regularizing or imposing deterministic patterns on the conditioned variation. However, the children who did not impose deterministic patterns did not necessarily acquire the variation patterns the adults did.

Ethnologue (http://www.ethnologue.com) is the most widely consulted inventory of the world's languages used today. The present review article looks carefully at the goals and description of the content of the Ethnologue‘s 16th, 17th, and 18th editions, and reports on a comprehensive survey of the accuracy of the inventory itself. While hundreds of spurious and missing languages can be documented for Ethnologue, it is at present still better than any other nonderivative work of the same scope, in all aspects but one. Ethnologue fails to disclose the sources for the information presented, at odds with well-established scientific principles. The classification of languages into families in Ethnologue is also evaluated, and found to be far off from that argued in the specialist literature on the classification of individual languages. Ethnologue is frequently held to be splitting: that is, it tends to recognize more languages than an application of the criterion of mutual intelligibility would yield. By means of a random sample, we find that, indeed, with confidence intervals, the number of mutually unintelligible languages is on average 85% of the number found in Ethnologue.

Calvert Watkins, a towering figure in historical and Indo-European linguistics and president of the LSA in 1988, died unexpectedly in Los Angeles on March 20, 2013, a week after his eightieth birthday. At the time of his death he was Distinguished Professor in Residence of the Department of Classics and the Program in Indo-European Studies at UCLA. He had moved to UCLA after a long career at Harvard, where he retired as Victor S. Thomas Professor of Linguistics and the Classics in 2003.

Why can't we say the asleep cat? There is a class of adjectives in English, all of which start with a schwa (e.g. afraid, alone, asleep, away, etc.), that cannot be used attributively in a prenominal position. A frequently invoked strategy for the acquisition of such negative constraints in language is to use indirect negative evidence. For instance, if the learner consistently observes paraphrases such as the cat that is asleep, then the conspicuous absence of the asleep cat may be a clue for its ungrammaticality (Boyd & Goldberg 2011). This article provides formal and quantitative evidence from child-directed English data to show that such learning strategies are untenable. However, the child can rely on positive data to establish the distributional similarities between this apparently idiosyncratic class of adjectives and locative particles (e.g. here, over, out, etc.) and prepositional phrases. With the use of an independently motivated principle of generalization (Yang 2005), the ungrammaticality of attributive usage can be effectively extended to the adjectives in question.