Nicki Minaj is sex. The diva-cum-rapper’s performances are routine—predictable beats, generally unimaginative lyrics, and trite themes of cockiness and sexuality—but she derives her success from the way in which she goes through the motions. With her incredible vocal-tone variation, sense of rhythm, and use of space, Minaj lends the ordinary a patent kinkiness.

In her sophomore album, “Pink Friday: Roman Reloaded,” Minaj taps into this prowess. While her lyrics are generally predictable and underwhelming, the album succeeds when Minaj does what she does best—being weird. However, when she shies away from her persona and turns to mainstream formulas, Minaj loses her shock factor and unique vocal delivery. Moreover, her songs’ lack of substance becomes apparent. Unfortunately, Minaj is far too normal for too much of the album. “Roman Reloaded” gives us only a fading taste of Minaj’s powerful quirkiness while we are barraged with poorly sung and produced mainstream rap.

On the album, Minaj often combines singsong vocals with crass lyrics to hilarious, ironic effect. “I am your leader, yes I am your leader / You’re not a believer, suck a big dick,” sings Minaj on the album’s third track, “I Am Your Leader,” her voice mechanical and staccato, perfectly matched to her in-your-face message. While repeated lines like “Put my dick in yo face” from “Come on a Cone” could easily fall flat, they are an entertaining break when Minaj sings them in an R&B diva vibrato.

Minaj’s attention to the importance of tone comes across even more strongly on the album’s opener, “Roman Holiday.” “My flows is sick and I’m a lunatic / And this can’t be cured with no elixa,” she raps, sighing out the last syllable of each line of the verse with a definitive “ha.” Between these emphases and the ridiculous fake British accent Minaj puts on when singing the hook—a refrain about how her alter ego should take medication and fix himself—it’s hard to shake the feeling that she’s mocking the listener and the unhelpful, overbearing voice of society’s authorities.

Within just this song, Minaj slides through several vocal registers and tones, creating the feeling of multiple speakers to match her self-professed multiple personalities. She expertly creates variation without losing the precision of her tone. The fourth track, “Beez in the Trap,” affords Minaj ample space for her vocal play. It opens with echoing, rhythmic pitches backed by a stuttering kick, and snaps instead of snare hits. The synth sticks to low bass tones, leaving Minaj with the entire middle to fill. On the bridge, she draws out her words in a way that sharply contrasts with her crisp delivery on the hook and verses. She’s whispery, casual, and indifferent. “Damn, damn, what they say about me? / I don’t know man, fuck is on your biscuit? If I get hit, swinging on a big bitch / I don’t know man, I’m shittin’ on your whole life,” she sings, transforming an otherwise uninteresting, even nonsensical passage into one of the better moments of the album.

When the album tries for sentimentality and mainstream pop, however, it flops. Tracks like “Champion” hint at Minaj’s potential, with lines like “This is that run-and-get-a-dollar-for-the-ice-cream-cone / ‘cause they killed my little cousin Nicholas / But my memories only happy images / This is for the hood, this is for the kids.” However the chorus about being a champion is tired and formulaic. Similarly, songs like “Beautiful Sinner” and “Young Forever” fall outside Minaj’s skill set by leaning on sung lines that are blandly delivered. Such simplistic mistakes abound throughout the second half of the album.

Minaj redeems herself on the album’s closer. “Stupid hoes is my enemy / Stupid hoes is so whack / Stupid hoes shoulda befriended me / And she coulda probably came back,” sings Minaj in a twisted childish voice on the already released “Stupid Hoe.” While here Minaj returns to her strengths for a powerfully bizarre finish, she would have done well to heed her own advice—had she paid attention to herself throughout the album and focused on her own quirky vocal abilities rather than conforming to conventional production and lyrical themes, she would have come back on her sophomore album much more strong.

—Staff writer Keerthi Reddy can be reached at kreddy@college.harvard.edu.