Some J-space stuff done on Gemma 4 31B, sensory L0-17, workspace L18-58, motor L59-59. "Think and answer only in English" lowers the CJK share at reply positions only modestly, from 24.5% to 19.4% at layers 42 to 52. A Chinese-only system prompt raises it to 34 to 40% in the reply, and already to 25 to 30% on the user's tokens, before a single reply token exists.
>no system prompt
reply 'The currency used in Italy is the euro. It is called the euro because it was adopted as a common currency by member'
user tokens L18-29: CJK 3.5% Cyr 2.7% | L30-41: CJK 10.9% Cyr 2.9% | L42-52: CJK 11.4% Cyr 6.5% | L53-58: CJK 11.3% Cyr 7.2%
reply tokens L18-29: CJK 3.3% Cyr 0.7% | L30-41: CJK 22.2% Cyr 4.4% | L42-52: CJK 24.5% Cyr 6.8% | L53-58: CJK 13.1% Cyr 6.1%
>"You are a helpful assistant. Think and answer only in English; never use any other language, script or characters."
reply 'The currency used in Italy is the Euro. It is called the Euro because it is the official currency of the Eurozone'
user tokens L18-29: CJK 3.3% Cyr 2.2% | L30-41: CJK 7.8% Cyr 2.1% | L42-52: CJK 10.7% Cyr 3.7% | L53-58: CJK 9.7% Cyr 4.8%
reply tokens L18-29: CJK 3.0% Cyr 0.5% | L30-41: CJK 19.3% Cyr 3.5% | L42-52: CJK 19.4% Cyr 5.4% | L53-58: CJK 12.2% Cyr 7.5%
>"你是一个乐于助人的助手。请只用中文思考和回答。" (control)
reply '那个形状像靴子的国家(意大利)使用的是欧元。它被称为“靴子”是因为其地理轮廓在'
user tokens L18-29: CJK 5.2% Cyr 4.8% | L30-41: CJK 17.0% Cyr 6.2% | L42-52: CJK 25.0% Cyr 6.9% | L53-58: CJK 30.0% Cyr 5.2%
reply tokens L18-29: CJK 9.2% Cyr 3.2% | L30-41: CJK 28.5% Cyr 5.0% | L42-52: CJK 34.2% Cyr 5.3% | L53-58: CJK 39.5% Cyr 3.1%