Split infinitives occur <u>when an adverb is inserted between two parts of an infinitive.</u>
Explanation:
By grammatical rules, inserting an adverb between the two parts of infinitive is non permissible. But <u>in normal usage it has been around liberally,</u> and often in ornate, literary language.
For example, an infinitive like 'to go' has been used often by
<u>'to boldly go'</u>
<u>'to gracefully go'</u>
These are proper usage phrases that occur often. a word added in between added to the general meaning of the phrase given here.