grammaticalize

/G R AH0 M AE1 T AH0 K AH0 L AY0 Z/
verb
  1. 1

    To make grammatical.

  2. 2

    To integrate into a system of grammar; to make (something such as a constraint) an element or rule of grammar, to cause (something) to be required by grammar.

  3. 3

    To cause (a word, a suffix, etc) to undergo grammaticalization.

Source: https://en.wiktionary.org/wiki/grammaticalize