Please speak more slowly.

American Sign Language:
Speak http://commtechlab.msu.edu/sites/aslweb/S/W3780.htm
slow http://commtechlab.msu.edu/sites/aslweb/S/W3701.htm
please. http://commtechlab.msu.edu/sites/aslweb/P/W2930.htm

Sign http://commtechlab.msu.edu/sites/aslweb/S/W3634.htm
slow http://commtechlab.msu.edu/sites/aslweb/S/W3701.htm
please. http://commtechlab.msu.edu/sites/aslweb/P/W2930.htm

English:
Please speak more slowly.

French:
Parlez plus lentement, s'il vous plaît.

Italian:
Per favore, parli più adagio.

Spanish:
Hable más despacio, por favor.

Swahili:
Tambaza maneno.