If you have payment of your housing, kid's schooling, and transportation expenses already arranged for, then you might be able to save 40% to 50% of your monthly salary. There's too many factors involved to give you a number with any certainty.
Basic cable (only one English channel, CNN) + high-speed Internet access will cost about 55 RMB's per month.
Electricity, gas, and water will cost another 150-250 RMB's per month, depending on your usage.
It's doubtful you'd have to pay association dues or maintenance fees for your apartment complex, but check to see if there are add-on fees. Ususally that's all included in the monthly rental charge.
Roughly estimate your Chinese cell phone will cost you about the same as it does in the States. There are a hundreds of phones to choose from, and the service monthly plans are similar to those offered in the West. There are only a few service providers. You can also opt for a pay-as-you-go plan. You'll probably need a local to help you sort all this out--someone that can communicate in English and Chinese. You'll find a neighbor or someone at the school that can help you.
Knowing English is not a necessity. There are plenty of people in China that understand some basic level of English in most places to help you. Most children are taught English in schools, and all university students must pass an English equivalency examination before graduation. You can almost always find a younger person to help you if you really need it. You can also get by in almost every situation with gestures. Shopping is easy because prices are listed in Arabic-Hindu (Western) numerals. You already know how to show 1 to 5 on one hand, and the hand signals on one hand for 6 to 10 are learned in 5 minutes. And there's always a calculator around in small shops and restaurants to negotiate and communicate prices. Converting from RMB's to USD's and U.S. measurements into metric are easy enough to do with a little practice. You'll get the hang of it quickly. Those awkward seconds of misunderstood communications are quickly resolved one way or another. Many signs are written in English or Pinyin, and lots of menus have photos. It won't take you too long to figure out what's inside a shop or building or store based on simple observations.  So don't worry about not knowing Chinese language when you arrive.
Some travel tips. You can usually get the address of a destination written in Chinese from the Internet. You can also use an Internet translator to convert your ideas to Chinese characters. If you don't have a printer, then you can write out the Chinese characters with the address information to show a taxi driver. Once you get to your destination look for a business card, brochure, or other materials with the name and address of your location for the next time you have to go there. Or go to a nearby hotel or business and get one of its business cards. You can also get someone to help you write out your home address, and then keep two copies with you at all times in different places. So if your wallet, purse, or backpack is lost you have a backup plan to get back home.
Theft is a problem in China, but you won't have to worry about being confronted on the streets. Theives act quickly by swiping a bag, laptop, or bike when no one is looking. Almost every corner or alleyway in China is safe for Westerners to walk about freely, day or night--assuming you're not doing something incredibly mindless that begs for you to be robbed. You can find a number of websites that give general advice about avoiding pickpockets and scams. But the threat of physical violence against you is extremely low.
On the other hand, safety and traffic are never mentioned in the same paragraph here. Forget everything you know about obeying traffic signs, road rules, speed limits, etc. No one else is paying attention to them. It's a free-for-all out there, so keep your eyes and ears open, and your head on a 360-degree swivel. A particular danger in Suzhou are the electric bikes and scooters that blow past you within inches at 35 kms/hr, often without a warning sound. And expect cars and bikes to drive in the dark with no lights on. No street, alley, or sidewalk is truly safe, so keep your wits about you at all times. No need to be scared. Just be aware of the dangers, and learn how to avoid them.
Food and water safety issues exist in a general sense, but they're nothing you can't adjust to quickly by following the common sense advice of others.
I hope this helps.
