Is it permissible for me to speak with my ex-husband during my waiting period ('iddah)?

If the waiting period (iddah) is due to a revocable divorce (talaq raj'i), then it is permissible to speak with the former husband, because some scholars consider a woman in revocable iddah to be like a wife. However, if the waiting period is due to an irrevocable divorce (talaq ba'in), then the former husband is considered a stranger (ajnabi), and it is not permissible to speak with him except out of necessity, provided there is no fear of temptation (fitnah) and no softness in speech.