Anyone who visits or works in Morocco will be granted more experiences and friendships by learning Moroccan Arabic.
This is the language most commonly used for daily conversation in much of Morocco. While related to Modern Standard Arabic, it has been significantly influenced by Berber dialects and French, and is distinct enough that it would not be followed by a Saudi or Egyptian.
Numerous languages are alive and well in Morocco. French is used for administration and business, and half the population speaks it on a daily basis. English is increasingly being taught to the younger generation. Multiple Berber dialects are on the rise.
Moroccan Arabic, however, is the street language of choice, and will provide you with direct access to the most interesting and beneficial aspects of Moroccan culture.