Language
The Language options control certain behavior of the assembler language.

User symbols are case sensitive
Toggles case sensitivity on and off. By default, case sensitivity is on. This means that, for example, LABEL and label refer to different symbols. When case sensitivity is off, LABEL and label will refer to the same symbol.
Macro quote characters
Selects the characters used for the left and right quotes of each macro argument. By default, the characters are < and >.
Macro quote characters changes the quote characters to suit an alternative convention or simply to allow a macro argument to contain < or >.

Allow alternative register names, mnemonics and operands
To enable migration from an existing application to the IAR Assembler for Arm, alternative register names, mnemonics, and operands can be allowed. This is controlled by the assembler command line option -j. Use this option for assembler source code written for the Arm ADS/RVCT Assembler. For more information, see -j.
No data reads in code memory
Use this option to generate code that should run from a memory region where it is not allowed to read data, only to execute code.
The option also affects the automatic library selection performed by the linker. An IAR-specific ELF attribute is used for determining whether libraries compiled with this option should be used.
This option can only be used with Armv7-M cores, and cannot be combined with code compiled for position-independence.