The known relation between the speed of a propagating wave, the wave length of the wave, and its frequency is
$$v=\lambda f$$ which is always true for any periodic sinusoidal waves.
1-a case were the wave is not sinusoidal but still periodic, like a sawtooth pattern say, that propagates with speed $v$, and of frequency $f$. It is obvious in this case we will not have a single $\lambda$ but infinite number of them, $\lambda_i$ (from Fourier analyzing that pattern). Can one define/calculate a new wave length $\lambda$ using $\lambda_i$'s such that $\lambda=v/f$?
2-another case where the propagating wave is not periodic, just a gaussian pulse say that propagates with speed $v$. Can one define something like $v=\lambda f$ in this case? how to calculate $f$ and $\lambda$ such that $v=f\lambda$