In January 2018, a New Deli newspaper reported a pattern of con men speaking to their prospective marks in their mother tongue to gain their confidence. One criminal gang actually trained its members to speak various Indian languages and even their dialects in different places for the purpose of getting access to the bank accounts of people who speak those languages.
That might not seem like a very good advertisement for the mother tongue – what I call the heart language. But it is. Speaking to someone in the language that is the most closely connected to their identity is indeed an excellent way to gain someone’s trust. Whether that trust is rewarded or betrayed is another matter. The mother tongue is powerful whether put to noble or ignoble purposes. It does indeed connect at the deepest level.
If grifters learn languages in order to hurt people, certainly missionaries, pastors and evangelists can learn them and translate the Bible into them in order to bless.