A lot of BASIC variants back in the early personal computer days had that feature too.. you only needed to enter as much of a keyword as necessary to make it unique. Or they had other abbreviations, like '?' for 'PRINT'. Anything to save a byte.
10 ?"hello whatever..."
which would be expanded to
10 PRINT "hello whatever..."
Line numbers counted too, IIRC, so it was more important when you had 4 and 5 digit line numbers.
But it's been 25 years since I did any commodore basic - my memory might be a bit wrong on this...
It also had only three error messages: "WHAT?" (any syntax-related problem), "HOW?" (any execution error that wasn't syntax-related, like division by zero), and "SORRY" (out of memory).