At the present moment, I have only tested Mamoru Itsuki -03:00 M1 for variances in the amount of tutorial text you get with different language settings. My findings are currently that there is no difference in the amount of tutorial text or time saved between the different selectable languages for Siren 2.

Mamoru Itsuki -03:00 M1 [JP] 7 texts to shibito, 17 texts to Yuri, 5 texts to shibito fight, 19 texts to the end = 48 [EN] 7 texts to shibito, 17 texts to Yuri, 5 texts to shibito fight, 19 texts to the end = 48 [FR] 7 texts to shibito, 17 texts to Yuri, 5 texts to shibito fight, 19 texts to the end = 48 [ES] 7 texts to shibito, 17 texts to Yuri, 5 texts to shibito fight, 19 texts to the end = 48 [DE] 7 texts to shibito, 17 texts to Yuri, 5 texts to shibito fight, 19 texts to the end = 48 [IT] 7 texts to shibito, 17 texts to Yuri, 5 texts to shibito fight, 19 texts to the end = 48 [RU] 7 texts to shibito, 17 texts to Yuri, 5 texts to shibito fight, 19 texts to the end = 48 [ZH-CN] 7 texts to shibito, 17 texts to Yuri, 5 texts to shibito fight, 19 texts to the end = 48

All "sub-goal" texts and the "scantling" weapon text does not stop gameplay, therefore these texts are not counted.