Hi Paridhi_Agrawal
I use a standard, cheap no-name USB Sound card (like this one DYNAMODE External USB 2.0 Sound Card Deals | Pcw) with a Galileo 1, running AlexT's version of Yocto.(See CMata's reference to go to AlexT's blog) It has been a while since I did the installation, but I am fairly sure it has ALSA included with it. If not, it is easy enough to install using OPKG
ALSA comes with the version of Yocto AlexT uploaded, but you need to run #opkg install usbutils to install the USB utilities
The only difficulty I had was that when i used a standard micro to USB cable to connect to a USB hub, the Galileo couldn't see the card, but when I bought a micro-USB to female USB connector i could plug the card into the adapter or run a Arduino type USB cable from the adapter to a hub, which has a Arduino/Printer type connector and use the card and other USB devices.
Attached is a small script that runs will cause the Galileo to recognize the card and play some sound files that are included in the repository. after you run the following two commands:
#modprobe snd-usb-audio
#alsactl init
you can use ALSA tools, aplay and arecord, as well as espeak (which is in AlexT''s AlexT_Intelrepository) for text to speech.
Any cheap speaker and/or microphone can be plugged into the USB sound card.
Hope this helps
rgb