Questions & Answers about Hætti dælan að leka?
English uses an '-ing' word here ('leaking'). Why does Icelandic use að leka?
In Icelandic, aspectual verbs like hætta (to stop) and byrja (to begin) are followed by að plus the infinitive form of the next verb. Icelandic doesn't use an '-ing' equivalent here, so 'stop leaking' is constructed as 'stop to leak'.
I thought the verb hætta forced the following noun into the dative case. Why is dælan in the nominative?
You are right that hætta governs the dative case for its objects (for example, hún hætti vinnunni, 'she quit the job'). However, in this sentence, dælan is the subject performing the action, not the object being stopped. Subjects are always in the nominative case. The action being stopped is the verb phrase að leka.
Is hætti present or past tense here?
It is the past tense. For the verb hætta, the third-person singular present tense is hættir (stops), and the past tense is hætti (stopped). Because this is a yes/no question, the verb jumps to the front of the sentence.
What is the base noun for dælan?
The base noun is dæla, which is a weak feminine noun meaning 'pump'. The -n at the end is the attached feminine definite article, turning 'pump' into 'the pump'.