Final answer:
Formal language is recommended for productive communication, while slang, technical language, and regional language may not be suitable in certain contexts.
Step-by-step explanation:
The recommended type of language to use for productive communication is formal language. Formal language is clear, direct, and conventional, making it ideal for academic writing and professional communication. It is important to use language that your readers will understand directly or from context, so avoiding technical language and regional language is advised. Slang language, although useful for expressing ideas quickly and vividly in certain contexts, is generally too casual for most academic and professional communication.