In unraveling his family history, writer William Poy Lee had no idea he’d wind up making a declaration of respectability for Toisanese across the America.

Yet there he was on stage, in the hoity-toity Asian Art Museum in San Francisco this month, publicly singing out salty, gritty Toisanese set to music, with his mother Poy Jen in the front row. He turned Toisanese – from household names to cuss words – into a performance.

It’s enough to make a self-respecting Chinese cringe. Toisanese is a Chinese dialect, but it is pure peasant-speak, in all of its graphic, roiling, diphthong-laced glory.

“Everyone said Toisanese was such an ugly language. Everyone,” said Lee, who dreamt up the idea of a jazz-like improvisation performance, based on ordinary words of his childhood tongue. Lee reconnected with the dialect while writing his memoir, “The Eighth Promise,” delving into why America’s first Chinese immigrants were such tough people.

Most of the first Chinese immigrants to the United States hailed from Toisan, one of four districts in the Pearl River Delta outside Guangzhou, known before as Canton. Once, 95 percent of the Chinese in the United States, from former Washington Gov. Gary Locke to Sunnyvale Councilman Dean Chu, traced back to Sze Yap, the four-district area where Toisan is located. Many of the people who inhabited San Jose’s early Chinatowns and built the Ng Shing Gung Temple in Kelley Park come from Sze Yap.

Up to the 1970s, you could speak Toisanese, also pronounced Hoisanese, to almost any Chinese-American from New York to Mississippi to San Jose and be understood.

Try to find “Toisan,” on the map, however, and you will only find “Taishan,” which is the word in Mandarin.

Unlike the most well-known big city, major dialects of China, Toisanese exists only on the tongue. “There are no Toisanese novels or opera,” Lee observes. “Bruce Lee never slipped into Toisanese.”

It sounds rough, as though you have pebbles in your mouth. “In truth it is a shout,” Lee said, one that might “include some finely sprayed spittle.”

Mandarin-speaking people cannot understand Cantonese, and frequently claim it hard to listen to. Cantonese-speaking people pronounce Toisanese inferior and hard to listen to.

Therein lies the crux of it. As he delved into his book, Lee delved into feelings of embarrassment about the dialect.

As a kid growing up on the streets of Chinatown, U.S.A., Toisanese or any Chinese got him benched at school. Even in Cantonese teachers rapped his knuckles for speaking Toisanese.

Then he began to think about Toisanese attributes for what they were: a hard-honed language that is inseparable from the land, unpretentious and tough-skinned. The words come “wrapped up like clods of dirt embedded with stones.”

As he thought about it, “Toisanese can arc over the rice paddies, go through a flock of noisy geese, cut through a stand of bamboo, and go around a hill,” he wrote. In short, it was designed for survival.

Yet, it had a musicality. The famous Tang Dynasty poetry, when read in Cantonese – or Toisanese dialect – rhyme, unlike in Mandarin.

Lee took a page from jazz to riff Toisanese words off of percussion and wind instruments to enliven his book readings. He collaborated with Layton Doung of Yellow River Drummers, and flutist Haley Wong to come up with an improvisational performance based on a “word score” of four parts: onomatopoeia, household words, salty cuss words and food-related words.

Some, like cable car, is an onomatopoeia, invented here, translated as “dang-dang car.”

“One guy said, ‘Hearing you guys doing it publicly with so much fun makes me feel me better about my language,’ ” Lee said. “It was an ‘Oprah’ moment – healing in front 130 people!”