Units for the relevant fields of teaching English to young learners (primary and pre-school) have been written by specialists in the field. You may find the following books helpful to support your knowledge in the areas of methodology and research:
Bland, J. (Ed.) (2015). Teaching English to Young Learners Critical Issues in Language Teaching with 3-12 Year Olds. London: Bloomsbury
Cameron, L. (2001). Teaching Languages to Young Learners. Cambridge: Cambridge University Press.
Legutke, M. K. / Müller-Hartmann, A. / Schocker-von Ditfurth, M. (2009). Teaching English in the Primary School. Stuttgart: Klett.
Mourao, S. / Lourenco, Mónica (2015). Early Years Second Language Education. International Perspectives on Theory and Practice. London: Routledge.
Murphy, V. (2014). Second Language Learning in the Early School Years: Trends and Contexts. Oxford: Oxford University Press.
Pinter, A. (2006). Teaching Young Language Learners. Oxford: Oxford University Press.
Pinter, A. (2011). Children Learning Second Languages. New York: Palgrave Macmillan.
E-LINGO subscribes to an action research approach to professional development. You may find the following publications helpful:
Burns, Anne (2010). Doing Action Research in English Language Teaching. A Guide for Practitioners. New York: Routledge.
Chevalier, Jacques .M. and Buckles, Daniel J. (2013). Participatory Action Research: Theory and Methods for Engaged Inquiry. London: Routledge.
Dörnyei, Zoltán (2007). Research Methods in Applied Linguistics: Quantitative, Qualitative, and Mixed Methodologies. Oxford: Oxford University Press.
Heigham, Juanita and Croker, Robert A. (eds.) (2009). Qualitative Research in Applied Linguistics. A Practical Introduction. Houndmills, Basingstoke: Palgrave Macmillan.
For students who read German:
Caspari, Daniela; Klipperl, Friederike; Legutke, Michael K.; Schramm, Karen (Hg.) (2016). Forschungsmethoden in der Fremdsprachendidaktik: Ein Handbuch. Tübingen: Narr.