I find most police or members of the public know enough English for you to get by. With a phase book or a phone app you will be fine.
Erdirne is good for a day trip and you really need to see the Selimiye Mosque, which was the magnum opus of the great Ottoman Architect Mimar Sinan, but it is a day trip.
https://www.kulturportali.gov.tr/por...miivekulliyesi
Aside from Izmir which ISTFlyer suggested is the city of Bursa perhaps the most beautiful city after Istanbul called Green Bursa in Turkish (Yesil Bursa) and draped around the foot of mount Uladag, it is famed for it's fruits and candied chestnuts (kestane sekeri). You can ride the teleferik cable car to mount Uludag, with views across the city. Drink Sarlep with cinnamon if it is cold, visit one of the famed thermal spas, buy silk products is the old silk market (Kozahan) and eat Iskender Kebab (I know people who drive from Izmir to Ankara via Bursa just for that).
You can catch ferries from Istanbul with with BUDO or IDO from multiple points around the city. Or you can get the Motorway which is now very quick, but make sure you have sufficient credit in the automated chargeing for tolls (HGS or OGS) as if I recall correct the fee is tl160 each way.
Have a nice trip.