Grammatical form and meaning

1.2.What is morphology grammatical form and meaning?
When analyzing grammar in this textbook, understanding the difference between FORM and FUNCTION is one of the keys to successful analysis of words, phrases, clauses, and sentence in their context.
To begin, our language can be seen as layers upon layers, and we can analyze our language from a variety of perspectives, for a variety of reasons. So the first point to remember is that you can identify, or name, a FORM at the word level, at the phrase level, and at the clause level. Similarly, you can also analyze how each FORM is FUCTIONING in the context of a sentence (or passage). Once again, you can identify the FUNCTION of a FORM at the word level, at the phrase level, and at the clause level.
FORM names things at the WORD level (noun, verb, adjective, adverb, preposition, relative, etc.), at the PHRASE level (main verb phrase, prepositional phrase, present participle phrase, past participle phrase, gerund phrase, infinitive phrase, etc.), and at the CLAUSE level (independent clause, dependent clause, subordinate clause, relative clause, nominal clause, etc.). There are lots of FORMS, but a finite number of FUNCTIONS.
In fact, there are only four (4) FUNCTIONS: 

1. 
   nominal - a noun or any group of words that can substitute for a noun (word, phrase, or clause) and perform nominal functions. In other words, they can do anything that a noun can do, including filling any of the common nominal slots in a sentence (subject, direct object, subject complement, or object of the preposition most commonly).
   
2. 
   adjectival - an adjective or any group of words that can substitute for an adjective (word, phrase, or clause) and perform adjectival functions. In other words, they can do anything that an adjective can do (modify nouns or nominals most commonly).
   
3. 
   adverbial - an adverb or any group of words that can substitute for an adverb (word, phrase, or clause) and perform adverbial functions. In other words, they can do anything that an adverb can do.
   
4.