THE number of people speaking Gaelic needs to increase by up to 860 a year to halt the decline in the language, according to a new report.
The research, published in a Royal Society journal, found the language was in danger of extinction because of the domination of English in everyday lives.
It suggests copying initiatives used to protect and develop Welsh which has been affected less by the historic "language shift" where one language is abandoned in favour of another.
The report says that during the 20th century, Welsh remained widely spoken despite long-term pressures for people to speak English. However, since the 1970s there has been a vigorous programme to revitalise the Welsh language.
The Royal Society report says Gaelic was the main language of the Highlands and Western Isles in medieval times, but drastic demographic changes, such as the Highland clearances of the 18th century, and the establishment of English as the language of education and advancement, were associated with increasing rates of a Gaelic-to-English shift.
The numbers of Gaelic speakers in Scotland has declined from about 250,000 in the 1891 Census to about 65,000 in 2001.
The report says 70 per cent of children aged three-15 speak Gaelic in households in which a married or co-habiting couple both speak Gaelic, while ?it is only 18 per cent if the male partner alone speaks Gaelic, and 27 per cent if the female does.
It says that 860 English speakers have to become bilingual every year (based on a Highland population of about 315,000) to counteract "natural wastage" as households with one or more Gaelic speakers fail to transmit the language to the next generation. This number could drop to 440 if the rate of passing down Gaelic at home could be increased.
John Angus MacKay, chief executive of Brd na Gidhlig, the national Gaelic development agency, said the report is encouraging as the figures quoted are broadly in line with their own to secure stability for the language.
He said: "My initial reaction is that this bears out that we are on the right lines with the plan approved by ministers for increasing numbers of children in Gaelic medium education, placing more emphasis on support for parents to use Gaelic in the home and aiming to increase the number of adult learners.
"For example we are aiming for a 15 per cent per annum increase in children going into Gaelic medium education for the next three years from a baseline of 390 in 2009-10, and an increase to 4,000 adult learners over the next three years. Our approach is akin to that adopted in Wales."
He said a plan approved by Scottish ministers to help create a new generation of Gaelic speakers will increase numbers of children in Gaelic medium education as well as the number of adult learners, and place more emphasis on support for parents to use Gaelic in the home.