You've done it more than once. Because some of them aren't pronounced the way they look. Those designer names, particularly the Italian ones, can be tongue twisters to say the least. I've done it myself but in my field it's an embarrassment. So in an effort to "save face", I'm breaking the common ones down, piece by piece.
Anna Sui is pronounced Anna Swee. (That one got me.)
Atelier should be Ah-tell-ee-ay.
Badgley Mischka is Badge-lee Meesh-kah. (I said Mishka.)
Bally: BAH-li. (Not Bally, that's too easy.)
Balmain: Bahl-mahhhhn. (Easy on the n).
Baume & Mercier: Bom ay Mer-SEE-ay.
Bottega Veneta: Bow-tay-guh Ve-NE-tah. ( Say what?)
Burberry: BURR-behr-ri. (Not Burberry, ok?)
Bvlgari: Bull-gah-ree. (What's the v for? Hell if I know.)
Byblos: BEEB-los. (Not the devil's name.)
Celine: seh-lyn. (Not the singer's name.)
Christian Loboutin: kris-tian loo-boo-tan. (Barely pronounce the n).
Dolce & Gabbana: DOL-cheh and Ge-BA-na.
Donna Karan: Donna Kah-ren.
Elie Saab: EH-li Zahb. (Don't think car.)
Emanuel Ungaro: Ee-MAN-noo-el OON-Gah-ro. (I was SO wrong.)
Emilio Pucci: Ehm-ee-lee-o Poo-chee.
Emporio Armani: Em-POHR-yo AR-mah-ni. (You can't go too wrong.)
Giambattista Valli: Gee-am-bah-tease-ta Valley. (Ok, that's a mouthful.)
Gianfranco Ferre: Gee-ahn-franco Feh-ray. (Not far away.)
Givenchy: Jee-von-shee. (Not give an inchie.)
Gianni Versace: Jee-YAN-nee Ver-SA-chee.
Guy Laroche: Gee Lah-Rosh. (Gee, Guy, who knows? Not I.)
Hermes: Er-mez. (Pretend there's no H.)
Helmut Lang: HEL-moot Lung. (Not how it looks, that's for sure.)
Herve Leger: Er-VEY Le-ZHAY.
Jean Paul Gaultier: Jhon Paul Go-tee-ay.
Lanvin: Lahn-vahhhh-n. (Long on the tongue.)
Louis Vuitton: Louie Vwee-tahhhhh-n. (Long on the tongue, again.)
Miu Miu: Mew Mew. (Like the cat, not the cow, lol.)
Moschino: Mos-key-no. (Like mosquito.)
Manolo Blahnik: Ma-no-low Blah-nick.
Narcisco Rodriguez: Nar-SEE-so-Rod-RI-gehz.
Proenza Schouler: Pro-en-zuh Skool-er. (Think back in "school " again.)
Pierre Cardin: Pyerr Kar-DOHN. (I said DAH, ha ha).
Ralph Lauren: Ralph LO-ren. (I thought it was Lor-REN. Who knew?)
Sonia Rykiel: Sewn-ya Ree-key-el.
Salvatore Ferragamo: Sal-va-TOH-reh Fehr a-GAH-mo.
Talbots: TELL-bots. (Not Tell-BO as I thought, like a French word.)
Thierry Mugler: TEh-ree MOOH-gleh.
Versace: Vur-sah-chee. (You knew that, I know.)
Yves Saint Laurent: Eve Sahn Lor-UHN.
YSL Rive Gauche: YSL Reev Gosh. (I want to say Goash!)
Hopefully these will save you some future embarrassment the next time you shop at Nordstrom or Holt Renfrew. As for me, I've got some memorizing to do!