Maxaa kugu dhacay - What happened to you?

Quick post - to say in Somali 'What happened?', we say,


Maxaa dhacay?


If you want to say, 'What happened to you?', we say,


Maxaa kugu dhacay? - What happened to you?


'kugu' is a combination of 'ku' (you) and 'ku' (preposition: 'to, with, by means of'). When you put the two ku's together, they become 'kugu'. 
Him, her and them don't have object pronouns, so if you want to say 'What happened to him/her/them?' , just use the preposition 'ku',


Maxaa ku dhacay? - What happened to him/her/them?


Other combinations,


Maxaa igu dhacay? - What happened to me?


Maxaa idinku dhacay? - What happened to you(plural)?


Maxaa nagu dhacay? - What happened to us(exclusive; not very common)?


Maxaa inagu dhacay? - What happened to us (inclusive; much more common)?