Having mused about the connection between Dutch -acht/-ocht endings and English -ought ending I was further interested to read David Crystal's comment on the word 'might'.
In Crystal's great book 'The Cambridge Encyclopedia of The English Language' he makes a study on the Middle English variations of the word might (note: the -ght ending). In this little aside he shows that the written evidence for this particular word during the Middle English period was varied due to scribal error, context or dialectal variant.
He adds as an example that the North Eastern dialect form of 'might' was 'micht'. Furthermore as David Simpson states in his fantastically entertaining book 'Aal Aboot Geordie', Northern dialect was chiefly influenced by Saxon (a West Germanic language) and not, as is commonly thought, Viking (North Germanic) languages. So we see that the Saxon (or North Eastern English) equivalent of might was close to 'micht'. This further proves a link between the -ght of English today and its equivalent Germanic -cht.