Some do so to dig into their roots or discover a new culture, while others see it as a way to upgrade themselves.
Madam Margaret Chew Siew Lan is taking Tamil lessons at the age of 65.
A polyglot who speaks many languages and Chinese dialects, the retiree has always wanted to learn Tamil.
She used to have colleagues from different countries in the firm where she worked for 26 years, which made computer hard disks. She picked up basic Tamil phrases from her Tamil-speaking co-workers, with whom she always wanted to communicate better.
Although Madam Chew had tried taking Tamil classes before, she was turned down as the courses catered only to children.
Around last October, she found out that a neighbour of hers is a Tamil tutor. Mrs Hemalatha Ramesh is the founder of Singa Academy, which offers Tamil lessons for children and adults.
'I told my tutor, treat me like I'm in kindergarten. I want to know more about the language because in Singapore, languages like Chinese, Malay and Tamil are important,' says the grandmother of two.
Madam Chew speaks English, Mandarin and Malay, as well as dialects such as Hainanese, Cantonese, Hokkien and Teochew. She understands but cannot speak Hakka. The widow has two sons, one of whom is deceased.
Like Madam Chew, some seniors are taking up new languages with enthusiasm, often abetted by having more time to pursue their interests in their retirement.
While some are curious about a language that is not their own, other seniors pick up their mother tongue language because they did not study it in school.
Though it may seem daunting, gaining fluency in an unfamiliar tongue is possible, even for the elderly.
Associate Professor Yow Wei Quin from the Singapore University of Technology and Design, who trained in psychology and has published research in bilingualism, says: 'The more motivated one is to learn a new language, the more time one spends in this endeavour, and the more willing one is to use the new language, the faster one will acquire conversational skills and fluency.'
Madam Chew has motivation in spades. She sometimes uses hanyu pinyin - a system of transliterating Chinese characters into Roman letters - to help her remember how certain Tamil words are pronounced.
She uses Google Translate when she texts Tamil greetings and phrases on her own initiative to her tutor.
While the advantages of early bilingualism are better known, learning another language as an adult can also be beneficial.
Dr Yow says: 'Bilingual children show some cognitive advantages such as when it comes to switching between tasks and certain aspects of memory, such as generalising information from one event to a later event. In older adults, bilingualism has been shown to protect cognitive function and delay the onset of dementia for about 4½ years.'
Bilingual children show some cognitive advantages such as when it comes to switching between tasks and certain aspects of memory, such as generalising information from one event to a later event. In older adults, bilingualism has been shown to protect cognitive function and delay the onset of dementia for about 4½ years. - Associate Professor Yow Wei Quin from the Singapore University of Technology and Design
Associate Professor Leher Singh, director of research at the National University of Singapore (NUS) department of psychology, was the lead author of a study which found that English/Chinese bilingual toddlers could pick out contrasts in sounds in a language they previously had no exposure to - in this case, an African language that has clicking sounds - unlike their English monolingual peers.
This suggests that learning another tongue 'opens up flexibility to other languages', including a 'perceptual openness to subtle distinctions in other languages', says Dr Singh, director of the NUS Infant and Child Language Centre.
Ms Mei-kwei Barker, director of English-language services at the British Council in Singapore, says: "Today, more seniors are working than ever before. Many of them feel the need to brush up on skills such as workplace communication in order to stay employable, socially connected and mentally active."
One of Mr S. Nagamuthu's three daughters encouraged him to take English classes at the British Council last year.
The 72-year-old had not had formal English lessons for 60 years since he dropped out of school when his father died the year he turned 12. To help support his family then, he worked as an office boy running errands.
A former shipyard worker, Mr Nagamuthu, who now works as a security officer in a secondary school, wants to speak well as part of his professional demeanour.
'Everything is in English. At the school I work in, I come into contact with visitors such as engineers and professors. I want to improve my grammar and vocabulary, I want to upgrade myself.'
Some seniors learn Mandarin for the first time partly to come to terms with long-held reservations about the link between one's language and cultural identity.
Like many in his cohort, retiree Richard Tan, 64, studied Malay instead of Chinese at school.
'I'm of the Merdeka generation. At that time, we were part of Malaysia. I can speak Malay, but I had always wanted to study Chinese. People at coffee shops and salespersons used to ask me, you are Chinese, how come you don't know Chinese? I didn't feel offended, but you do ask yourself, how come?' says the bachelor, who retired from the logistics industry two years ago. He recently completed a basic Mandarin course at Han Hai Language Studio in Kramat Lane.
A growing interest in Chinese culture prompted Madam Rosalind Tan, 66, to learn Mandarin. She has been taking classes for several years at NUS, subsidised by the National Silver Academy.
Madam Tan, who studied Malay as a child, took many courses in subjects she was interested in when she was younger - including French, Korean, calligraphy and music - so much so that 'learning became a habit'.
The retired realtor, who has two daughters and three grandchildren, thus had no hesitancy in enrolling for Mandarin lessons in 2015 because she became interested in tea culture and tea appreciation. Her fellow hobbyists mostly spoke Mandarin and Hokkien.
For Madam Tan, who reads books about China's history and of Tang poetry, the interest in her Chinese roots is also deeply personal.
The tomb of her grandparents rests in the grounds of Bukit Brown Cemetery.
Madam Tan played a leading role in the discovery of the long-lost graves in 2011, through a process that involved tracing her grandparents' death records.
She finds it meaningful that she can understand the Chinese inscriptions on the joint tomb of her grandparents, such as one she translates as, 'Don't forget the graceful sounds and good reputation of your ancestral home.'
Madam Tan says: 'These are words of wisdom from ancestors to descendants. I'm more aware of my actions now as they reflect my family's values. I hope such ancestral teachings can be passed down through the generations. Now I have learnt Chinese, I understand my roots better.'