There are actually two elements to this question.
The meteor shower speed categories listed in various publications using terms like "fast", "very slow", etc., are in general based on the atmospheric entry velocities of the meteors in question. This velocity measurement runs from approximately 11 to 72 km/sec (very slow to very fast), and is dependent on the direction from which the meteors approach the Earth. The Taurid meteors, which we see each autumn from Britain, are slow-moving, so are passing through space in a fairly similar direction to the Earth, having an atmospheric entry velocity of about 25-30 km/sec. The Perseids, which peak in mid-August annually, are swift-moving by contrast, with a velocity of almost 60 km/sec on average, as they approach the Earth from more nearly head-on.
However, the apparent shower meteor speeds you can see under the sky do not always match such broad expectations, because the apparent angular velocity of a given meteor, usually measured in degrees per second, effectively depends on its distance from the meteor's radiant and the elevation of the meteor above your horizon. This is because the meteor is an object moving in three-dimensional space relative to you as an observer on the Earth's surface, so you will be only rarely viewing a meteor which passes at right-angles to where you are (when it would show its greatest apparent angular motion). For example, a meteor moving directly towards or away from you will have both a very short apparent path in the sky, and be very much slower moving than you'd expect from the simple "Perseid meteors are fast" concept.
The IMO's tables are so seemingly complex, because they're trying to provide a workable guide for visual observers which take into account these variables - different atmospheric entry velocities, different meteor heights above the horizon, and different distances between the meteors and their radiants.
So, we can't estimate "typical" angular meteor velocities for shower meteors, but we can estimate the likely average apparent velocity meteors from a given shower should show as we view them from Earth, by using the atmospheric entry velocities listed in places like the IMO's annual Meteor Shower Calendar
(direct link to free download of the 2015 PDF version). Table 5 on page 25 of this 2015 Calendar
has a convenient listing of the average atmospheric entry velocities for each shower under the "V-subscript-infinity-symbol" column, in km/sec (sorry; can't do the right formatting to show this symbol combination here, but see p.24 of the Calendar
for what I mean - it's the fourth item on the "Abbreviations" list).
If you're searching on the Web more generally, you may also run across other meteor velocity measurements which aren't so helpful for surface-based observers, commonly "V-subscript-H" and "V-subscript-G". The first is the heliocentric velocity (effectively the orbital velocity of the particle around the Sun, hence "helio" = Sun), the second the geocentric velocity, which is the particle's velocity compared to the theoretical centre of the Earth. Neither of these are of use to an Earth-surface observer, so are best avoided, unless you wish to explore meteor orbital dynamics.