Heaney uses several maritime metaphors in discussing a poem set in a sea-faring culture. Here he refers to speech that is ‘unmoored’ and then to lodging his own ‘linguistic anchor’ on the ‘Anglo-Saxon sea-floor’.  If you have ever felt, in being immersed in another language, that you are slipping your moorings in your own, this should resonate.

This was during the middle years of the 1980s, when I had begun a regular teaching job in Harvard and was opening my ear to the unmoored speech of some contemporary American poetry.  Saying yes to the Beowulf commission would be … a kind of aural antidote, a way of ensuring that my linguistic anchor would stay lodged on the Anglo-Saxon sea-floor.  Beowulf, Seamus Heaney (London: Faber & Faber, 2000 (1999)), p. xxiii