It's probably slipping on the pulleys. Belt tension is loose or it may need lubrication (yes belts do need it occasionally) A few drops of dish soap are a good bet or a little motor oil but that may break down the belt in the long run.
You may need to adjust the tension on the belt.
Yes
Your squeal may be more of a whistle which could indicate a small vacuum leak.
That depends on how, when and where it is squealing. For example, if the brakes squeal when applied, the brake pads are probably worn down. A squeal from the engine compartment whenever the engine is running could be a loose serpentine belt (especially if the squeal changes a little when you rev the engine).
squeal is a lose belt or one of the accessory will need to be replaced soon
Most likely it is a belt on your car. Usually the squeeling is from a loose belt while idling and will also make noises while driving.
It's either loose or you have a bearing going out on idler or an accessory.
Change the belt
Change the belt
you have a bad belt in you engine you to have it replaced or if it isn't to bad you can use some belt sqeal stopper you can get from most auto stores
The belt will not generally squeal, but the water pump often makes a "Scrapy-scrapy-scrapy" sound.
Maybe the tires? If it is in the engine compartment, it is probably either a loose belt or one is getting old and slipping.