The phrase "till so far" is not commonly used in English, but if it were, it would likely be spelled "till" with two "l's" and "so far" as two separate words. "Till" is pronounced /tɪl/ and refers to a monetary payment or a farming tool. "So far" is pronounced /soʊ ˈfɑr/ and means "up until now." It's important to use correct spelling and pronunciation to communicate effectively in English.