Hebrew and Arabic don't have letters for vowels.
Modern Hebrew and Arabic have "punctuation" to lend context to the reader to decipher the vowels.
Thus, in ancient Arabic...
Hbrw nd Rbc dn't hve lttrs fr vwls.
Mdrn Hbrw nd Rrbc hv "pncttn" t lnd cntxt t th rdr t dcphr th vwls.
By only adding vowels, how much can you change those sentences. Go for it in the comments!