radio luminosity versus linewidth for UCHII regions, HCHII regions, young stellar wind sources, and jets (see Hoare et al. 2006 source of these data). Unlike in Hoare et al. (2006), here we have plotted the half-width-zero-intensity (HWZI) for the recombination lines rather than FWHM. For the UCHII and hyper-compact H II regions this does not make a great deal of difference, but some stellar wind sources appear to have a narrow optically thin component which dominates the FWHM whilst a broader optically thick component dominates the HWZI. In these cases the HWZI gives a better indication of the kind of speeds the wind is attaining. However, it is a more difficult parameter to work with since where the line returns to the continuum is dependent on the signal-to- noise of the spectrum. We have also added the two massive YSO jet sources that have measured proper motions to this plot: GGD 27 and Cep A2. These have been corrected for the inclination where known and thus measures the full speed of the gas. It is unfortunate at present that the jet sources are not amenable to IR spectroscopy to probe their line profiles as they are deeply embedded and not 