As the instrumentalists of the River Oaks Chamber Orchestra arrived at The Church of St. John the Divine for a routine rehearsal, some were equipped with an unusual technology gadget: A Madonna headset with a microphone. This was not the beginning of a typical music session.

Don't let Alecia Lawyer's perky disposition fool you. The ensemble's founder and executive director is always up to something, such that concerts always include surprise selections and unscripted moments. The bubbly redhead's strategy is to keep audiences guessing and coming back for more, and this time, the musicians were included in her devilish scheme.

Commissioning new works — 28 since the group's inception — and challenging her colleagues is par for the course at ROCO.

The orchestra is set to premiere Paul English'sLumière LunaireSaturday, 5 p.m. at the church with an encore performance with dinner at The Houstonian Hotel on Sunday, 5 p.m. Also on the program is Haydn's Cello Concerto featuring principal cellist Richard Belcher and Schubert's Symphony No. 4. Conductor Kazem Abdullah makes his ROCO debut.

The headsets are for musicians to sing in sprechstimme style, which lives somewhere in between speaking and singing, with notated pitches and rhythms. The technique is associated with the sonorities of the Second Viennese School — think Alban Berg, Anton Webern — and credited to Arnold Schoenberg's Pierrot's Lunaire.

Musicians have a love-loathe relationship with the iconic serial work. In theory classes, it's unavoidable. When performed badly, it's more pleasant to hear nails against a blackboard than to endure the 40-minute melodrama. It's genius. It's high German cabaret gone wrong.

Director Bruce LaBruce's March 2011 unorthodox staging at the Hebbel am Ufer Theatre in Berlin included castration, dildos and gender blurring.

The character of Pierrot, after all, is a man played by a woman.

"I remember conservatory days in our classes having to stretch ourselves and sing different parts of score," Lawyer says. "It was a special skill not called upon in an instrumental profession, but we all had to go through that in the name of music education."

Re-imagining Pierrot in the moonlight

Lumière Lunaire nods to Pierrot. The composer found inspiration in the commingling of energies between the 100th anniversary of Pierrot, whose paradoxical world propelled JoAnn Falletta — a favorite guest conductor at ROCO — to write poetry.

"I conducted Pierrot once in my life and I'll never forget it," Falletta tells CultureMap. "The experience was in some ways difficult and frustrating, in others magical. It is quintessential Schoenberg, reinventing the music world while remembering the language of Late Romanticism.

"It was a calling he had no control over."

Falletta writes poetry to remember special moments in her life — like the first time she led Richard Strauss' Der Rosenkavalier and Ravel's Piano Concerto in G Major. These little poems, which help crystallize her experiences, are stored in a personal diary not to be shared with the public. But when a friend suggested her words could help non musicians understand how it feels to perform a work, she published her first anthology, Love Letters to Music.

Falletta's text doesn't reinterpret Shoenberg's Pierrot, it responds to her memory of it. It's lighter than the original.

The words re-imagine Pierrot as a bittersweet clown. He's supposed to make us laugh, and we do, yet's he's suffering, frustrated in love while standing alone coddled by the moonlight. Pierrot doesn't fit in and lives in an undercurrent of regret and sadness, not unlike Schoenberg when he moved from Romanticism to Serialism.

Paying homage to Pierrot and his creator

English's music doesn't copy Schoenberg, either. He pays homage to his whole body of work while placing Falletta's words in focus. It's not just an addition, it's a text setting. Like Schoenberg, English doesn't exploit the poem.

"Falletta's fresh take on Pierrot caught my attention, " English says. "It's an English poem as a reflection of a German setting of a French text. All those different elements gave me the ability to compose in a variety of different styles. I was free to draw from anything as long as it described the poetry and the central character."

Houston knows English as a jazz pianist, even though that's only 20 percent of the composer's activities. His Lumière Lunaire is removed from jazz and employs tonality, expanded tonality, some difficult yet accessible scoring and even sections that are gentle for listeners not familiar with contemporary music traditions.

Most of the writing shifts from short solo riffs accompanied by light orchestration to a few full tutti passages. The texture is light as to allow the singing, speaking and sprechstimme to cut through clearly.

For Lawyer, sprechstimme has another function beyond the aesthetic: It allows audiences insight into the players of the orchestra. It's something else to talk about.

"The vibrancy of classical music is not the actual music, but the relationship between audience and musician that is facilitated by the language of music," Lawyer says. "Composers provide the poetry and prose for us to communicate.

"Commissioning allows ROCO to have our musical conversations in the present as well as sharing our own interpretations of the past."

Lumière Lunaire is exactly about that:A tête-à-tête about a work from yesteryear that still influences today, reconstructed by those close to the people of ROCO.

The River Oaks Chamber Orchestra in Concert presents music of Paul English, Haydn and Schubert and features principal cellist Richard Belcher and conductor Kazem Abdullah. Tickets to the Saturday performance start at $25 and tickets to the Sunday encore with dinner at the Houstonian start at $95.