This documentary takes an in-depth look at the life and work of avant-garde musician, Frank Zappa. (  / Sony Pictures Classics)

Whether appearing on “Crossfire” or testifying before Congress, Frank Zappa always had plenty to say. So it’s not too bizarre that German director Thorsten Schütte would devote an entire movie to the cult musician’s words rather than his music. The resulting documentary, “Eat That Question: Frank Zappa In His Own Words,” is amusing and even edifying, although it is also unlikely to make converts out of those who just don’t get Zappa’s pastiche of juvenile parody and sophisticated songwriting, derived from rock, jazz and 20th-century experimental music.

Frank Zappa was known for his music, but a new documentary focuses on his interviews. (Photo by Joe Corsage, Courtesy of Sony Pictures Classics)

Snippets of songs, along with larger chunks of a few compositions, are heard in the documentary, which was assembled entirely from existing footage. But the emphasis is on the Baltimore-born guitarist’s public comments. Fortunately for Schütte, Zappa was usually eager to step in front of a microphone. In 1963, he showed up on “The Steve Allen Show” as a clean-cut young composer who had written a concerto for instrumental ensemble and two bicycles. Later, he appeared on the game show “I’ve Got a Secret,” as well as countless serious arts programs in Europe. He even granted a lengthy television interview while in the final stage of the prostate cancer that killed him in 1993.

In one clip, an older Zappa identifies himself as a conservative; he clearly didn’t like either the Old or the New Left. But he was actually more of a libertarian, outraged by censorship and the very notion that a word can be “dirty.” He wanted to be free to say whatever he liked, a license that “Eat That Question” happily grants him.

R. At Landmark’s E Street Cinema. Contains coarse language, brief nudity and smoking. 93 minutes.