Dr Elizabeth Stark

She was also a world ranking scientist in her chosen field of speech therapy, despite having ended the first stage of her formal education at 14.

By the time of her death in Indiana, US, she was internationally recognised as a leader in the field of communication disorders.

Betty, who in her younger days was known as Rachel, was born in Glasgow, the daughter of a civil servant. The family moved to London as her father pursued his career but she was evacuated from there aged 14. As a teenager she had to keep house for her brothers and father after her mother fell ill. She passed the London University entrance exams by correspondence course but the family could not afford to finance her further education.

It was a return to Glasgow at 16 which allowed her to attend a three-year non-graduate teacher training course, courtesy of two aunts who had taken it upon themselves to raise the funds for the fees. She recalled one of her tutors as a ''formidable lady'' who was the founder of speech therapy in Scotland. Betty signed up for the first Scottish courses which led to qualification as licentiate of the London College of Speech Therapists. She worked by day as a primary school teacher and at night studied with medical students.

Weekends were spent at Glasgow hospitals where she gained sufficient clinical experience to allow for a career change to a role as a school speech therapist. She also found time to qualify as a licentiate of the Royal Academy of Music, London.

Betty had sufficient determination and spirit to be able to resist her father's expectation that his daughter should remain patiently at home until marriage beckoned. She threw herself into the activities of a small repertory theatre company and went climbing with the Scottish Ladies' Mountaineering Club. Mountaineering became a passion, firstly in Scotland and then on the Austrian Alps, in Arctic Norway, and Nepal. She wrote of her adventures for the Scottish Field, the Scots Magazine, and other journals. In 1955 she visited Nepal as a member of the first

all-women's expedition to the Himalayas. The venture was

jointly financed by the publisher Collins, and Life magazine. Betty co-authored a book about the trip, Tents in the Clouds, with a close friend, Monica Jackson.

As climbing became increasingly technical she found her addiction to the mountains eased. She described herself as being not very good at technical climbing with its increased reliance on pulleys, rope slings, hammers, and pegs.

In her professional life she was a pioneer in infant speech development, creating the first coding system for describing the sounds infants make and the transition

to first words. She wrote many papers on her research in that

field and lectured at universities throughout the world on language development and language problems arising from genetic and

neurological diseases.

Her doctorate in communication disorders was awarded by the Oklahoma Medical Center in 1965. Three years previously she had graduated in speech pathology from Northwestern University.

She was director of the division of communication sciences and disorders at the Kennedy Institute in Baltimore, Maryland, before becoming professor of audiology and speech sciences at Purdue University Indiana (1987-91). She is survived by her second husband, Wilford Morris, whom she married in 1997. Her first husband, Herbert Seitz, died 1984. They had no children.