Can we use though and although interchangeably? Somebody told me that the difference is that though cannot be used at the beginning of a sentence. Is that the rule?
Though can definitely be used at the beginning of a sentence, and has a long history of doing so. Consider Isaiah 1:18 from the King James Bible:
TheFreeDictionary.com cites this usage rule:
However, this seems overly fussy and prescriptive. Consider the following:
Those sound to me like perfectly fine English. They would be perfectly fine using although as well. That, to me, feels like interchangeability, pure and simple. In fact, I can think of no examples in which though cannot be used interchangeably with although. Though your mileage may vary.