It's the IBM PS/2 Speech Adapter card, capable of LPC and CVSD-format playback via the TI TMS5220C and Motorola MC3418 chips, respectively. The card is basically unusable without the external speaker/headphone box that attaches to the mini-DIN port.
Here is an auction for the complete card/speaker pairing:
http://www.ebay.com/itm/IBM-PS-2-Speech-Adapter-Kit-P-N-1501216-New-Un-Used-Parts-/230728393606
There's been some recent discussion about the Speech Adapter (PS/2 and PCjr) on Mike Brutman's forum:
http://www.brutman.com/forums/viewtopic.php?f=1&t=360
Here is a list of (mostly educational) software purportedly compatible with the Speech Adapter:
Access Software
Amazon: Guardians of Eden
Countdown
Links: The Challenge of Golf
Compton's
MultiMedia Encyclopedia
Hartley Courseware
Project STAR
Brick by Brick (series)
The Money Series
IBM
Bouncy Bee Learns Letters
Bouncy Bee Learns Words
Exploring Measurement, Time, and Money - Level I
LinkWay
Primary Editor Plus
Spelling - Level I
Storyboard Plus 2.0
Writing to Read
Public-Domain LinkWay folders:
Bullet Firing: Stroboscopic Photography
NewsLink: On-Line Newspaper
COB ON A COT: Primary Reader
Purdue University
Cliff's Notes: Huckleberry Finn & Oliver Twist
Elegy Written In A Country Churchyard
Other products providing Speech Adapter compatibility include IBM's ACPA and Audiovation cards, Digispeech's DS201A and DS301A (and possibly the DS311), and DoubleTalk's PC/LT products.