Second albums are supposed to be difficult, but Speedy Ortiz makes it look easy on the terrific Foil Deer. After a striking debut (Major Arcana) and memorable follow-up EP (Real Hair), charismatic Sadie Dupuis and company have polished their distinctive sound without abandoning the anything-goes sensibility that’s made them so intriguing. The quartet long ago absorbed the basics of brainy early ’90s guitar bands (Pavement, Pixies et al.) and has fashioned its own language. Like Arctic Monkeys frontman Alex Turner, Dupuis unleashes a torrent of words, seemingly inspired by rap artists to put her idiosyncrasies front and center; like Bettie Serveert’s Carol van Dijk, she’s a deceptively authoritative singer who has mastered the art of appearing poised and anxious at once, hinting at deep reserves of barely controlled emotion. With songs ranging from sludge (“Zig”) to brisk pop (“Swell Content”) to mutant funk (“Puffer”), Dupuis’ often-oblique lyrics touch on longing, loss, and the difficulty of genuine interaction, creating the sensation of eavesdropping on free-form musings. Whether exclaiming, “I was the best at being second place but now I’m just the runner-up” in “The Graduates,” or reflecting on “a heartache that numbs you even when it coats you” in the hushed “Dvrk Wvrld,” Dupuis is an endlessly intriguing presence.