I am afraid that we ourselves do not use Git as our internal source control system and thus I cannot provide better advice than google or other forums.
The dictionary files do not change over time and perhaps you can consider distributing them only when needed so they can stay locally on the machines that need them. This kind of defeats the purpose of source control, but if the source control you use cannot handle such files I am not sure you have many options. You could try to cheat it by renaming them in the source control (e.g., to a txt extension), but that's another manual step for the users.
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