atom
British Acorn Computers' first microcomputer BASIC was a slightly improved version of its "Acorn System BASIC", and both were a, well, very peculiar dialect of the language.
Atom BASIC was a 32-bit integers BASIC. Floating-point support, with 40 bits, could be added by a ROM expansion. This expansion also included a full set of floating-point versions of the original statements and functions.
It is certainly one of the few that did not implement some "roots" language keywords which existed in the original Dartmouth BASIC such as DATA, READ and DEF.
By then common, the PEEK and POKE brothers are absent as well. Both were replaced by the ? character, which was not the commonly used abbreviation for PRINT, but would either read or set the byte at a given memory location:
PRINT ?3200 ?3200 = 255
The ! character would be similarly used as a "long version", for reading or writing 4-byte values.
While $ is commonly used as suffix for string variables, in Atom BASIC it could be used as prefix, actually an operator, which would read or write sequences of ASCII character codes ended by Carriage Return (CR). This was used to add string support to the original Acorn Systems BASIC. It kinda looked like the strings implementation mode famously pioneered by HP Time-Shared BASIC, but would not allow proper "array slicing" operations. LEN and CH were the only string functions available.