 In articulatory phonetics, consonants are classified according to the parameters place and manner of articulation and voicing. For an acoustic classification we use frequency patterns, portions of silence and we know that consonants have no clear-cut formant pattern. The first and most obvious parameter that allows us to identify consonants is the absence of vocal fold vibration in voiceless consonants. In ASA there is no visible vocal fold vibration and thus no fundamental frequency. ASA by contrast involves vocal fold vibration and thus has a well-defined fundamental frequency. This allows us to differentiate between voiceless consonants and any other voiced sound. The type of consonant, whether voiceless or voiced, can be classified by additional acoustic properties. For example, all plosives such as APA, ATA and AKA involve a significant portion of silence and a short portion of friction noise when they are aspirated, the so-called burst. The characteristic feature of fricatives such as AFA, ASA and ASHA is the clearly marked portion of friction noise. And according to the frequency range and intensity of that noise, fricatives can be kept apart. Other consonants such as trills like ARRA can be identified by regular patterns of vibration and small closures in between. Or they even have visible formant patterns like nasals such as ANA or approximants like AWAR. Yet the formants are not as clear-cut as in vowels. Consonants influence their environment. Look at these two vowels, R and E. In isolation they have a steady formant pattern. However, if we put a K in between and say AKI, we have an additional narrowing in the vocal tract which alters the shape of the central resonance chambers, the pharynx and the aural cavity. So consonants considerably influence the formant patterns of the vowels with which they occur. This effect is referred to as formant transition. Let us now identify the consonants within a more complex spectrogram. Clearly, in this example we have at least two fricatives without a fundamental frequency. They both involve high frequency friction noise and must therefore be voiceless alveolar fricatives. Furthermore, we have three portions of silence, again without fundamental frequencies, so we have three voiceless plosives. The first is almost unaspirated since it involves a very short burst. The second is well aspirated and number three, even though it occurs finally, is also aspirated, which means that here we have additional friction noise. In fact, we have two vela and one alveolar plosives. Furthermore, we have two vowels, a high vowel and a low vowel, and a de-voiced alveolar approximate with low frequency friction noise and a nasal consonant with a clearly identifiable F0 but no clear-cut formant pattern. The result is what I created for you, a screencast.