An inexhaustible copiousness and readiness of speech
An insatiable appetite for trifles
An insatiable voracity
An inscrutable mystery
An intentional breach of politeness
An interchange of civilities
An intolerable deal of guesswork
An involuntary gesture of remonstrance
An irrelevant bit of magniloquence [magniloquence = extravagant in speech]
An irrepressible and impassioned hopefulness