The sons made eleven eels of themselves, and the Gruagach their father was the twelfth. They went around in the water, searching in every place, and there was not a stone in the river that they passed without looking under and around it for the old fisherman’s son.
And when he knew
(а когда он понял; to know /knew, known/ – знать; понимать, осознавать) that they were after him (что они гонятся за ним; after – после; /движение вслед за кем-л./ за, вслед за), he made himself into a salmon (он превратился в лосося); and when they knew he was a salmon (а когда они узнали, что он стал лососем), the sons made eleven otters of themselves (сыновья превратились в одиннадцать выдр), and the Gruagach made himself the twelfth (а Груагах стал: «сделал себя» двенадцатой).
And when he knew that they were after him, he made himself into a salmon; and when they knew he was a salmon, the sons made eleven otters of themselves, and the Gruagach made himself the twelfth.
When the fisherman’s son found
(когда сын рыбака обнаружил; to find /found/ – находить; обнаруживать) that twelve otters were after him (что за ним гонятся двенадцать выдр), he was weak with hunger (он был слаб от голода), and when they had come near (и когда они приблизились: «подошли ближе»), he made himself a whale (он превратился в кита: «сделал себя китом»). But the eleven brothers and their father (а одиннадцать братьев и их отец) made twelve cannon whales of themselves (превратились в двенадцать огромных китов: «сделали двенадцать пушечных китов из самих себя»; cannon – пушка), for they had all gone out of the river (потому что они все /уже/ выплыли: «вышли» из реки), and were in the sea now (и теперь были в море).
When the fisherman’s son found that twelve otters were after him, he was weak with hunger, and when they had come near, he made himself a whale. But the eleven brothers and their father made twelve cannon whales of themselves, for they had all gone out of the river, and were in the sea now.