The left speaker is not working and there is an odd sound of speeding up and slowing down. Is that from the belt? If so how do I get to the belt to replace it?

There is no dinger as the other guy suggests . sound comes from the driver door speaker .
The audible warnings alert the driver of a system concern or a critical vehicle condition. The radio generates the audible warnings through the left front speaker. The radio receives audible warning requests via the class 2 serial data line. If the radio receives multiple audible warning requests, the warning with the highest priority sounds first. On vehicles with an audio amplifier, the amplifier instead of the radio generates the audible warnings and receives audible warnings requests via the class 2 serial data line. Either the radio or the audio amplifier is the chime producer. The following lists the audible warning priority and the pulse rate:
Fast rate chime (150 pulses per min)
Medium rate chime (100 pulses per min)
Slow rate chime (50 pulses per min)
Turn signal reminder (will pulse at turn signal flasher rate)

Your best bet ,wear your seatbelt . so the sound goes off . If you do wear the seat belt and the chime sounds ,have a qualified repair shop check it .

just a guess but it sounds like a Crank Position Sensor, or a Speed Sensor. Always include vehicle make, model & year. Include any strange information: (sounds, noises, recent performance info. for a better answer when asking a question about your vehicle.

Have the car put on a rack and have the noise listened to with a mechanics stethoscope to confirm the wheel bearing is at fault.

it is always good practice to replace idler pulleys , seals , hydraulic adjuster when replacing a timing belt as the everything is worn out as well
It is now possible that the idler bearings for the belt are failing
If the pulleys , crank and cam seals and hydraulic adjuster were all not replaced with the belt then they job will have to be done soon

Yes, I'd have it back to them to rectify issues.

you could possibly have a bad universal joint on the driveshaft or half shafts

Tell me when you speed up is the heater set on hot and high speed?????
WHEN you slow down is the fan still going at the same speed or dose it go very slow when on idle.
If the Fan stays on high but runs cold when going about 80 in top but when you speed up it gets hot and then back off slightly then its sounds like Water pump isent pumping the water around the engine correctly ,but then it should make the engine run overheated.or it could be a slipping fanbelt, but then that should make the Alternator to make a noise,so {throttle to 2000 rpm from idle standind still} and see if there's a noise coming from the water pump area.
The belt should have just a little free movement more on the longest part of the belt(a very little about 1/8' movement
So check it out and let ne know how you get on .
Ron

Try taking a bar of soup when vehicle is idleing touch it to the sides of the belts your not soppost to use belt spray on surpinten belt But if maltaic sound prositests then water pump or belt tenisioner problem is likelywater pumps wil normaly leak through a hole called the weep hole when there going and you won;t hear matelic noises but the belt tenisinor yes they are a ware part and need to be replaced more often then water pumps and are assocated that kind of noise

well if it is your hubs going bad the noise will (#1) speed up and slow down with the speed of the car moving!!( because the hubs only move when the tires move)but if the noise speeds up and slows down with the car in park and only reving the engine than it is not your hubs!!! will end up being a bearing going bad on a pulley that is turned by the main v-belt( BELT TENSIONER PULLEY, power steering,water pump,a/c clutch,ect.)

Check the power steering fluid level. Left is torque side and probably tightens the belt as right it would loosen the belt a little so check the belt for sloppyness too. Hope this helps, The Raz