Arnold Wall was born on 15 November 1869 at Nuwara Eliya in Ceylon (Sri Lanka), the sixth of nine children of George Wall, a coffee planter and merchant, and his wife, Mary Ann Dixon. He had five half-sisters from his father's first marriage. With some of his brothers and sisters he was sent to live with a family friend at Clevedon, near Bristol, England, before going to boarding school near London in 1879.
As a young man Wall held a number of low-paid teaching positions in private schools, and studied French and English part time at the University of London, graduating MA in 1893. He then taught for four years at the University Correspondence College in Cambridge, and was one of the first to obtain, in 1897, a Cambridge BA degree by thesis rather than by examination. His research into the Scandinavian elements in English dialects provided the basis for his later expertise in philology.
While employed at the University College of Wales, Aberystwyth, in 1898, Wall applied successfully for the chair of English language, literature and history at Canterbury College, New Zealand. He arrived in Christchurch in February the following year. Relinquishing history in 1906, when James Hight was appointed, Wall remained professor of English for another 25 years. His main area of interest was Anglo-Saxon language and literature, and this influenced the study of English at Canterbury in his time. He cultivated a stern and distant manner in public, and students found his lectures dry and uninspiring. He had the reputation of never smiling in class, even when indulging his considerable gift for witty and sardonic comment. The warmer side of his personality Wall reserved for his family and close friends.
Arnold Wall married Elsie Kent Monro Curnow, whose father was a schoolmaster, in Christchurch on 13 November 1901. They were to have two daughters and one son. Elsie Wall died suddenly of pneumonia in 1924; her husband remained a widower for the rest of his long life.
Wall became a strong advocate of reforms to improve the academic standing of New Zealand's tertiary institutions. He played a leading role in introducing the nine-unit degree course which allowed students to do advanced work in their chosen subjects. He was also one of the professorial group that fought, with limited success, for the abolition of the system whereby New Zealand students had to pass examinations which were set and marked in England. Wall was a member of the Senate of the University of New Zealand from 1918 to 1926, and his forthright expression of opinions led to some bitter personal conflicts.
At Canterbury College, too, Wall's dealings with the board of governors and his fellow professors were often far from harmonious. He was prominent in the long struggle of the professorial board to gain representation on the board of governors (finally achieved in 1922), and led the professorial board's unsuccessful resistance to the appointment of a rector as academic head of the college. Wall had little respect for the first of his colleagues to hold this position, Charles Chilton, and when James Hight was appointed Chilton's successor in 1927, Wall's scorn and disappointment at being overtaken by an academic junior were publicly aired in a satirical poem published in the Press. In it he expressed ironical approval of the election by the 'horses' of 'Good, kind Dobbin' as their king, in preference to 'a thoroughbred'.
This was just one of many of Wall's mostly lyric and epigrammatic poems published in the Press and elsewhere. His poetry is distinguished by its technical skill, its elegance of expression, and its close and witty observation of human and natural phenomena. Despite this, and his prolific output (he published 10 collections), Wall's work has been largely ignored by New Zealand critics.
Aside from his academic and literary pursuits, Wall had a love of outdoor activities and an intense interest in nature. Slim and athletic, he was a keen walker and experienced mountaineer, having climbed several major peaks in Europe. In New Zealand, mountaineering expeditions in the Southern Alps led to a specialist interest in botany. In 1915 he began collecting specimens of alpine flora for his friend, the botanist Leonard Cockayne, and acquired a thorough knowledge of New Zealand plants. In the 1920s Wall became honorary keeper of the herbarium in the Canterbury Museum. He added several thousand sheets of specimens to the collection, mostly gathered by him on trips to the mountainous regions of both islands. Wall discovered a number of new plant species and varieties; seven of these bear his name. He wrote numerous scientific papers and popular articles on botanical subjects.
Wall had a facility for explaining complicated or specialised subjects in a manner that appealed to ordinary people. He developed this talent by contributing articles on a range of subjects to the Press. After his retirement from Canterbury College in early 1932, he achieved wider recognition through his popular writing. In the 1930s a regular series of articles in the Press under the title 'Our mother tongue' established him as an authority on the correct pronunciation and use of English. Wall was highly critical of New Zealanders' speech; he considered it to be inferior to the Received Standard of English pronunciation. In his influential book, New Zealand English (1938), he interpreted the characteristic features of the New Zealand accent as faults to be corrected.
It was through the medium of radio that Wall reached his largest audience. He had given occasional radio talks before, but in February 1955 he began regular fortnightly and later weekly broadcasts under the title 'The Queen's English'. In these programmes he discussed points of English usage and responded to listeners' queries about language with a clarity of thought and speech that brought him a devoted national following. Forced to discontinue broadcasting by failing eyesight in May 1961, Wall had within three months, at the age of 91, begun another weekly column in the Press, 'The jeweller's window'. For 5½ years this entertained readers with its mixture of linguistic, philosophical and autobiographical items.
Wall's intellectual vigour in old age was matched by his physical strength. He continued climbing until a few years before his death and his mountaineering feats, including an ascent of Mt Isobel near Hanmer at the age of 84, made him something of a celebrity. Arnold Wall was appointed a CBE in 1956 and the University of New Zealand conferred on him the honorary degree of doctor of literature in 1960. He published his autobiography, Long and happy, in November 1965. Arnold Wall died in Christchurch on 29 March 1966 at the age of 96.