Catholic Social Teaching, even while affirming the right of sovereign nations to regulate immigration, nonetheless also teaches us that all people have the right to emigrate when they are unable to provide economic security and safety for themselves and their families.  While most immigration to the U.S. is currently from Asia, the rhetoric of the Trump campaign was focused solely on "Mexico" - code for Spanish speakers, despite the fact there is actually net out-migration to Mexico.

People do not leave their countries for frivolous reasons - they leave because they are desperate. Catholic Social Teaching affirms that we are to remain focused on the dignity of the person and the welfare of families. Because U.S. immigration quotas are low, desperate people cannot and will not wait for a Visa that will never come.

Your point about road signs is ludicrous - I've driven in Italy and other countries where I do not speak the language.