Bibliography:
- Borsley, R. D., Tallerman, M., a Willis, D. (2007), The syntax of Welsh (Cambridge: Cambridge University Press).
- Bybee, J. (2006), ‘Diachronic linguistics’, yn Geeraerts, Dirk, a Cuyckens, Hubert (goln), Cognitive Linguistics (Oxford: Oxford University Press), tt. 945‒87.
- Bybee, J., Perkins, R., a Pagliuca, W. (1994), The Evolution of Grmmar: Tense, Aspect and Modality in the Languages of the World (Chicago: University of Chicago Press).
- Danchev, A. (1989), ‘Language change typology and adjectival comparison in contact situations’, Folia Linguistica Historica,9 (2), 161–74.
- Davies, J. (2007), A History of Wales (London: Penguin).
- Davies, P., ‘Identifying word-order convergence in the speech of Welsh-English bilinguals’, traethawd PhD, Prifysgol Bangor, Bangor, 2010.
- Davies, P. (2016), ‘Age variation and language change in Welsh: Auxiliary deletion and possessive constructions’, yn Durham, Mercedes, a Morris, Jonathan (goln.), Sociolinguistics in Wales (London: Palgrave Macmillan), tt. 31‒59.
- Deuchar, M., Webb-Davies, P. a Donnelly, K. (2018), Building and using the Siarad corpus of spoken Welsh: Bilingual conversations in Welsh and English (Amsterdam: John Benjamins).
- Ellis, N. C., et al. (2001), Cronfa Electroneg o Gymraeg (CEG): A 1 million word lexical database and frequency count for Welsh, <http://corpws.cymru/ceg/> [Cyrchwyd: 16 Chwefror 2018).
- Heine, B., a Kuteva, T. (2005), Language Contact and Grammatical Change (Cambridge: Cambridge University Press).
- Heine, B., a Kuteva, T. (2010), ‘Contact and grammaticalization’, yn Hickey, Raymond (gol.), The Handbook of Language Contact (Malden, MA: Blackwell), tt. 81‒99.
- Jones, M. C. (1998), Language obsolescence and revitalization: Linguistic change in two sociolinguistically contrasting Welsh communities (Oxford: Oxford University Press).
- Mair, C. (2004), ‘Corpus Linguistics and grammaticalization theory: Statistics, frequencies and beyond’, ynLindquist, Hans, a Mair, Christian (goln.), Corpus Approaches to Grammaticalization in English (Amsterdam: John Benjamins), tt. 121‒50.
- Matras, Y. (2010), ‘Contact, convergence, and typology’, yn Hickey, Raymond (gol.), The Handbook of Language Contact (Malden, MA: Blackwell), tt. 63‒80.
- Mittendorf, I., a Willis, D. (2004), Corpws Hanesyddol yr Iaith Gymraeg 1500‒1850/A Historical Corpus of the Welsh Language 1500‒1850 (Cambridge University, adnodd electronig), <http://people.ds.cam.ac.uk/dwew2/hcwl/menu.htm> [Cyrchwyd: 9 Ionawr 2020].
- Ó Siadhail, M. (1989), Modern Irish: Grammatical structure and variation (Cambridge: Cambridge University Press).
- Parry-Williams, T. H. (1923), The English element in Welsh: a study of English loan-words in Welsh (London: Honourable Society of Cymmrodorion).
- Prys, D., Prys, G., a Jones, D. B. (2016), ‘Cysill Ar-Lein: a corpus of written contemporary Welsh compiled from an on-line spelling and grammar checker’, yn Calzolari, Nicoletta; Choukri, Khalid; Declerck, Thierry; Goggi, Sara; Grobelnik, Marko; Maegaard, Bente; Mariani, Joseph; Mazo, Helene; Moreno, Asuncion; Odijk, Jan; Piperidis, Stelios (goln), Proceedings of the Tenth International Conference on Language Resources and Evaluation (LREC 2016) (Paris, Ffrainc: European Language Resources Association), <http://dblp.org/rec/conf/lrec/PrysPJ16> [Cyrchwyd: 9 Ionawr 2020].
- Thomas, A. R. (1982), ‘Change and decay in language’, yn Crystal, David (gol.), Linguistic controversies: Essays in linguistic theory and practice in honour of F. R. Palmer (London: Edward Arnold), tt. 209‒19.
- Thomas, P. W. (1996), Gramadeg y Gymraeg (Caerdydd: Gwasg Prifysgol Cymru).
- Thomason, S. G. (2001), Language contact: An introduction (Edinburgh: Edinburgh University Press).
- Thomason, S. G., a Kaufman, T. (1988), Language contact, creolization, and genetic linguistics (Berkeley, CA: University of California Press).
- Traugott, E. C., a König, E. (1991), ‘The semantics-pragmatics of grammaticalization revisited’, yn Traugott, Elizabeth Closs, a Heine, Bernd (goln.), Approaches to Grammaticalization (Amsterdam: John Benjamins), tt. 189‒218.
- Willis, D. (2008), ‘English-Welsh language contact in the realm of negation’, papur a gyflwynwyd yn Transmission and Diffusion Congress ym Mhrifysgol Radboud yn Nijmegen,Ionawr 2008.