严格来说 / 严格地说,[clause]
[clause],确切地说 / 准确地说,[clause]
严格来说 and 确切地说 both tighten a statement, in two directions. 严格来说 – "strictly speaking" – applies the exact definition, often to admit that a common label doesn't quite hold. 确切地说 – "to be precise" – follows something rough and replaces it with something exact. Both are neutral to formal, common in explanations, reports and careful speech.
The clause after 严格来说 often qualifies or contradicts what people usually say.
严格地说 and 严格说来 are the same phrase in other forms.
确切地说 usually comes mid-sentence, after a first rough version.
准确地说 is interchangeable with it.
English can tack "strictly speaking" on at the end. These phrases go before the clause they qualify.