I. What is the comparative grammar aspect of language change, that is, how do grammars differ at different stages of the evolution in a given language.
II. What are the diachronic sources of the linguistic changes that we observe, including sources in language acquisition by children, sources in the instability in the language usage of adults, and sources in language/dialect contact.
Here is a preliminary list of the topics to be covered:
1. The nature of grammatical change.
a. grammatical variation: comparative variation and grammar change
b. a potential source of grammatical change in mislearning by children.
c. another source of changes in innovations in language use by adults.
Anthony Kroch. 1999. Syntactic Change. in Baltin and Collins, Handbook of Syntax, Blackwells.
Anthony Kroch. 2005. Modeling language change and language acquisition. LSA Institute Forum Lecture.
Ian Roberts. 2007. Diachronic Syntax. Oxford University Press, chapters 3 and 4.
2. Grammatical change as the result of language contact: focus on the case of change in v2 in English as a result of Scandinavian influence
Ian Roberts. chapter 1.
Michel DeGraff. 2009. Language Acquisition in Creolization and, Thus, Language Change: Some Cartesian-Uniformitarian Boundary Conditions. Language and Linguistics Compass 3(4):888-971
Kroch, Taylor and Ringe. 1995. The Middle English Verb-Second: A Case Study in Language Contact and Language Change.
Kroch and Taylor. 1995. Verb Movement in Old and Middle English.
Augustin Speyer. 2007. Topicalization and Clash Avoidance: On the interaction of prosody and syntax in the history of English. UPenn dissertation.
3. Syntactic change due to morphological change; for example, the loss of agreement and the apparent loss of V-to-T.
Bobaljik. 2002. Germanic Inflection: Why Morphology Does Not Drive Syntax. JCGL
Heycock et al. 2003. Verb movement and the Philosophers Stone.
Heycock and Wallenberg. 2013. How variational acquisition drives syntactic change: The loss of verb movement drives syntactic change: The loss of verb movement in Scandinavian. JCGL
4. Variation and change in the domain of OV and VO order
Ian Roberts. 2007. Diachronic Syntax. Oxford University Press, chapter2, section 5.
Eirikur Roegnvaldsson. 1987. OV Word Order in Icelandic.
Anton Ingason et al. 2012. Anti-social syntax: Disentangling the Icelandic VO/OV parameter.
Lieven Danckaert. 2017. The loss of Latin OV: steps towards an analysis.
More cases to be investigated.