Julius can change recognition grammar while running.
It is implemented in a server-client mode called "module mode".
There is a Japanese document to explain the function, and I'm now translating it to English.
Anyway, I guess you can see how it works by trying the procedures below:
1) Launch Julius in module mode, specifying at least one grammar.
julius -C .... -module
2) Launch jcontrol in another window and connect to the running Julius.
"localhost" should point to the host where 1) is running.
jcontrol localhost
3) When julius recognize input, it will be sent to jcontrol and output to stdout.
4) At jcontrol, type command "pause" and hit enter. Then Julius will stop recognition.
a command "resume" will re-start the recognition.
5) Prepare a grammar like "foo.dfa" and "foo.dict" on jcontrol side, and try a command
changegram foo
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