The fun started 13 years ago, when Susan Picillo left a kooky message for a Houghton Mifflin executive from a Boston pay phone.

“I kept changing voices,” says Picillo, a lecturer in communication studies at Northeastern University. “I did a little kid, and a gangster, and a cliché dumb blonde.”

Her bravura performance paid off. It convinced the publisher to hire her as a voice-over actress for the Curious George interactive CD-Rom series, in which she played a park ranger, a fruit vendor and a character Picillo describes as a “plump, happy, pearl-wearing” aviatrix.

It also launched her career in the voice-over industry.

Picillo, who can do a rip-roaring impression of Ethel Merman channeling Bruce Springsteen, sums up the secret to her outspoken success: “It’s all about trying different things and playing with sounds.”

Her keen understanding of the power of drama and song helps her there. In the late 1970s, Picillo studied acting at Emerson College, then moved to New York “to seek fame and fortune on the stage,” she says, playing Anya in Anton Chekhov’s “The Cherry Orchard,” and Sarah in Stephen Sondheim’s musical “Company.”

She’s still a working musician. Her band, Susan E. and Bluesliner, plays a “powerhouse blend of blues, soul, R&B and funk,” according to its Facebook page.

“My favorite venue is standing in front of a live audience and singing,” says Picillo, whose heartfelt rendition of T-Bone Walker’s song “Call It Stormy Monday (But Tuesday Is Just as Bad)” has been known to leave a few tears in its wake.

Picillo prides herself on keeping her voice in great shape. Before gigs on stage or in the studio, she drinks plenty of water, abstains from coffee and takes a hot shower to loosen up her vocal chords.

In her public speaking and articulation classes, Picillo prescribes vocal exercises to students like an athletic trainer prescribes shoulder exercises to baseball players.

“If you make your living by using your voice, it’s in your best interest to protect it like a pitcher protects his arm,” she says.