About a month ago a small green love-bird departed from its cage in a Prescott Street apartment and set our to explore the neighborhood. With the anxiety of an expectant father, Roman Jakobson, Samuel Cross Professor of Slavic Languages and Literatures and owner of the bird, stayed up all night waiting for her return. The next morning she wandered in blissfully and Jakobson, with mild censure, returned her to the wire, webbed cage. Such concern is not rare in Jakobson. Those who know him say that he is a devoted man-attached to his studies, to his friends and students, and, of course, to his bird.

Jakobson's assiduous studies of philology show his most intense zeal. Throughout his life he has worked excessively, both in residence at universities and on vacations. When he was wrapped up in a problem during his youthful days in Prague, he would frequently work 36 hours without sleep.

Despite the long hours. Jakobson puts in at his desk, he is in excellent health. He has always maintained his physical condition by taking long walks along country roads. While in Czechoslovakia, he and his wife used to walk 230 miles from Bruno to Prague whenever a visit to the city was necessary. When he is staying at his favorite Czech farmhouse in the Catskills, he takes regular hikes and, according to his former secretary, will almost break river ice for a morning swim. A year ago while Jakobson was hiking along a highway, a car struck him. For an hour he lay helpless until an ambulance finally came, and doctors say only his excellent physical condition saved him from death. The accident left him with a slight limp, but he uses a came only in icy weather.

Jakobson developed walking as a hobby on his frequent study trips to primitive central Russia. He was born in Tsarist Moscow and a childhood interest in the structure of poetry led him to his present field-Slavic linguistics. As a student in Russia he was outstanding and had achieved a knowledge of some obscure Silberian dialects by the time most people enter college. Jakobson soon became disillusioned with the new Communist government and in 1920 moved to Prague.

In the Czech capital Jakobson built his reputation as a linguist and his researches resulted in scores of important monographs. He mixed crudite dissertations with vitriolic polemic against the rising Nazi Party. Later, when the Germans invaded his adopted country, Jakobson, who was then living in Brno, became a refugee for the second time. "Few people knew the Germans were going to invade the next morning," he says. "The news was announced on the radio and we left Brno for Prague the same night. This time we didn't walk, however, for there was no time. I had to burn my valuable letters; what ashes they made!" After hiding in Prague for three weeks Jakobson and his wife escaped to Denmark with the help of some friends. During the next year he and his wife shuttled all around the Scandinavian countries, finally settling in Oslo.

When the Germans overran Norway in April of 1940, Jakobson field to Sweden and finally to the United States. In this country he received a teaching position at Columbia and continued his work on the Igor Tale, the focal point of all his study. He has been devoting virtually all his research time to this Russian epic, and it is the main concern of his seminars.

When the University enlarged its Slavic department in 1949, Jakobson and his wife came to Harvard-he as a professor of Slavic and she as a lecturer in Czechoslovakian. But Harvard got more than two new additions to its Slavic staff since most of the devoted graduate students who were working with Jakobson at Columbia followed the scholar up to Cambridge.

In Cambridge, Jakobson and his wife have settled in an apartment on Prescott Street. Typical of a scholar's living quarters, the flat's living room is dominated by a massive desk littered with papers. Books scattered through the room are beginnings to collect under the windows. At night, all the local Slavic students trickle into the apartment for little chats with Jakobson; they stop in with a question, to solicit encouragement, or to draw Jakobson into an illuminating discussion. Employing his unbelievable energy even in conversation, he gesticulates constantly, emphasizing his remarks with a stab of his hand, or by running a hand through his unkempt hair when puzzled.

When not doing research or conversing with friends, Jakobson usually retreats to an overstuffed chair with a book of poetry or a portfolio of primitive art reproductions. Although he occasionally spends an evening writing or chucking through a Marx Brothers movie, he feels most contented with his research. Jakobson, an Indefatigable and painstaking worker, attributes hard work to the nature of his field. "Philology," he says, "is the art of reading slowly."