Speaking is more formal and organized than talking; in some contexts they may be interchangeable.
Financial and cash (even when used with an adjectival function) are not interchangeable. Cash problems are a subset of financial problems; one can have a financial problem (how to pay a credit card bill if your salary hasn't yet been credited to your bank account, for example) that have nothing to do with cash (physical money - notes and coins).
Paintings (made with paint) are simply not the same as drawings (which are drawn). (If those definitions aren't clear enough, use a monolingual dictionary. I say 'monolingual' because some languages don't make the same distinction.)
Before 'classical style/manner' - in that context - you need an article. Style and manner may be interchangeable, though in some academic contexts (when talking about art) I expect there's a difference.
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