About 40 per cent of Lundayeh, especially the younger generation, also no longer speak or understand their mother tongue.
Persatuan Kebudayaan Lundayeh Sabah President, Pengiran Lalung, said children of most Lundayeh families living in urban areas and some in the villages can only speak a little in their mother tongue.
"My rough estimation showed only about 60 per cent of our Lundayeh people now can speak in their mother tongue," he said, when met.
Pengiran shared his concerns at a seminar organised by the association at Kem Bina Negara in Kundasang which was officiated by State Resource Development and Information Technology Minister Datuk Siringan Gubat.
Pengiran said apart from this they are also facing a problem in terms of writing in their mother tongue.
"Writing in the mother tongue is actually our main problem, which we have strived to resolve the last 10 years. But this is more or less resolved now with the publication of our dictionary called 'Kamus Lundayeh-English' by the Culture and Art Ministry which is now used by individuals and at schools," he said.
He said they also supported Siringan's call to the Kadazandusun Cultural Association (KDCA) Thursday to introduce a "Mother Tongue Month" to boost efforts to encourage every ethnic community to converse in their respective mother tongue at home with family members and friends, as part of the month-long Tadau Kaamatan celebration due in May.
"On our part, I will bring up during our annual general meeting scheduled for March 25 suggestions how to boost the use of our mother tongue in our community," he said.
He said their plan is that this would start firstly at home and from there expand. "As for the Lundayeh association or related non-governmental organisations, it would start with the meeting where we would use the mother tongue in communication and writing the minutes.
"For the church Mass we would try to have at least once a month where we would use our mother tongue in prayers," he said.