Much ink has been spilled over the difference between sentences like “It is I” versus “It’s me.” What this matter comes down to, of course, is the coherence between stylistics and grammar, in case there is a choice. That is why in contemporary English, whenever a speaker chooses to utter the answer to the question, “Who is it?,” will use the objective form of the pronoun with a contracted copula (i. e., “It’s me”) and the subjective (nominative) form of the pronoun with the full (uncontracted) form of the copula (i. e., “It is I”, as stilted as this may sound in contemporary speech).
The underlying reason for this particular outcome has to do with the stylistic value of contraction. As between contracted and uncontracted forms, contraction always involves the colloquial (informal) stratum of the linguistic means at one’s disposal, while the uncontracted form is coherent with the formal stratum. Hence the variation of the form of the copula in the construction at issue.
My redoubtable fitness trainer, Daniel J. Mulroy, Jr., whom I see regularly for workouts at the Prospect Rehabilitation Center in Manchester Center, VT., informed me yesterday that he had done a bit of field work in connection with my preceding blog post, to wit: Dan queried each of the seven participants in a stretching class he teaches as to how they pronounced the word mantra. Without exception they all responded by saying that their pronunciation accorded with the currently ubiquitous [mántrə]. Sic transit gloria mundi!
The word mantra is an early borrowing from Sanskrit via Hinduism into English, the donor language’s meaning being (according to the Oxford English Dictionary Online) ”A sacred text or passage, esp. one from the Vedas used as a prayer or incantation; a word or phrase from a sacred text repeated in this way. Also: a holy name, for inward meditation.” Its present-day occurrence, especially in the media, comes with the meaning (as defined in the OED): “A constantly or monotonously repeated phrase or sentence; a characteristic formula or refrain; a byword, slogan, or catchphrase.”
The traditional pronunciation renders the initial vowel as that of the garden-variety English word man, i.e. the flat vowel [a]. The ubiquitously erroneous pronunciation, heard constantly in the media, however, takes the word mantra as esoteric, hence marked (cf. my article in American Speech 72 (1997), 437-439), and identifies it with that of song, i.e. the broad vowel. This mispronunciation is clearly and directly the outcome of ignorance of the word’s traditional normative rendition in English, again due to imperfect learning.