Should 'they are not understood' be accepted as well?
No that would not be correct.
Waht you are saying is "Hawaeleweki"
Kufahamu means to know.
The word fahamiki has been modified or in swahili "imenyambuliwa".
if kufahamu means to know, why would sikukufahamu translate with I did not understand you ó_Ò
you haven't conjugated the verb, so 'fahamu' in that context still means 'to know'
I made a post on verb conjugations here
nobody said it would be easy but words getting a different meaning when being conjugated...? also it is difficult (for me as a German) to understand grammar explained in English; but thanks anyway