Which is correct - 'Looking forward to speak with you' or 'Look forward to speak with you'?
Neither "Looking forward to speak with you" nor "Look forward to speak with you" is grammatically correct.
The correct phrase should use the gerund form of the verb, which is "speaking." Here are the correct versions:
Using "speak" as an infinitive verb, as in "speak with you," is incorrect. The correct form must use "speaking" to specify the ongoing form of communication.