Is holding a foreign woman's hand to keep her from intermingling with men in the Haram, if she doesn't understand Arabic, considered forbidden?

Strive to warn and prohibit women from crowding men, using legitimate means. Touching one of their hands is not part of this endeavor; rather, it is falling into what you have been forbidden from. Ibn Majah narrated from Aisha, may Allah be pleased with her, that she said: "By Allah, the Messenger of Allah, peace and blessings be upon him, did not take an oath from women except what Allah commanded him, and the hand of the Messenger of Allah, peace and blessings be upon him, never touched the hand of a woman at all." Al-Shinqiti said in Adwa' al-Bayan: "The fact that the Prophet, peace and blessings be upon him, did not shake hands with women at the time of giving allegiance is clear proof that a man should not shake hands with a woman."