# Why are signals of carbon and hydrogen atoms (in NMR spectra) split by coupling to 19F?

Why signals of carbon and hydrogen atoms (in NMR spectra) are split by coupling to $\ce{^{19}F}$? Some spectra books only states that

$\ce{^{19}F}$ (natural abundance 100%) has a spin quantum number I of ½. The signals of carbon and H atoms up to a distance of about four bonds are split by coupling to $\ce{^{19}F}$.

but there is no explanation. Could someone please explain why $\ce{^{19}F}$ can couple with H or C and split their signals.