If you say “He don’t know nothin’ ” in an interview for a white-collar job, you won’t get the job. And if you say “tike” instead of “take” and you drop your “aitches everywhere” the way they do “down in Soho Square,” you will earn the scorn of Professor Henry Higgins:

“Look at her — a pris’ner of the gutters;

“Condemned by ev’ry syllable she utters.”

But what if you committed yourself to improving your command of English? And what if your tutor was as brilliant as Professor Higgins, who boasted that in six months he could remake the flower girl Eliza Doolittle so completely she could pass as a duchess at an embassy ball? And you did it?

What an extraordinary illustration of how language influences the way others perceive us. Language is power, and “My Fair Lady” makes the point delightfully. If you fail to learn to speak properly, not only do you miss an opportunity to use language to your advantage, but you also risk being admonished by the likes of Professor Higgins:

“Remember that you are a human being with a soul and the divine gift of articulate speech; that your native language is the language of Shakespeare and Milton and the Bible; and don’t sit there crooning like a bilious pigeon.”

With such full-throated opprobrium for those who misuse our language, you’d think Alan Jay Lerner would get the grammar right in the script, but twice I was yanked from the magic of the Guthrie Theater’s marvelous production by glaring errors.

The first was committed by the prim and proper Mrs. Pearce, who says to Eliza’s suitor Freddy Eynsford-Hill, “Whom shall I say is calling?”

Whom shall I say is calling?

According to traditional English, “for whom the bell tolls” is correct, as is “to whom it may concern” and “I don’t know whom to blame,” but it should be “Who shall I say is calling?” The relative pronoun takes the case — either the subjective who or the objective whom — of the clause in which it functions. You wouldn’t say, “Whom is calling?” so you shouldn’t say, “Whom shall I say is calling?”

Similarly, it should be “I don’t know who is at the door.” Even though who is the object of the main clause, it functions as the subject in its own clause. Likewise, it should be “I don’t know who deserves my vote,” just as it should be “I don’t know whom to blame.”

The second glaring error was committed, ironically, by the transformed Eliza herself when she declares, “Oh, God, I wish I was dead.” Verbs can be expressed in three moods: the indicative, the subjunctive and the imperative. Here Eliza uses the indicative was when she should have used the subjunctive were to express something she wishes would happen.

I find beauty in all forms of English, from high to low, but this is a play about acceptable language. Let’s hope director Joe Dowling has the courage and good sense to correct those errors in future productions.

Stephen Wilbers offers training seminars in effective business writing. E-mail him at wilbe004@umn.edu. His website is www.wilbers.com.