With the average life expectancy in especially developed countries steadily increasing, healthy ageing is prioritised on the research agenda. Most recently, several later-life activities have been related to improved mental and cognitive health. One of these activities is language learning. Indeed, in the light of the reported advantages of lifelong bilingualism, various studies have looked into bilingualism as a possible anti-ageing tool to delay the onset of symptoms of degenerative diseases like Alzheimer's, with as perhaps the most promising recent line of work intervention studies that introduce bilingual experiences to older adults in the form of foreign language courses meant to induce a protective effect on cognitive decline. Unfortunately, the scant studies available have not found convincing results, most likely due to several pitfalls in their designs, one of the most important being that method of instruction is rarely specified or controlled for. In this paper, we identify methodological concerns that need to be addressed when conducting experimental work related to later-life language learning, resulting in a research agenda for later-life language learning studies.