physical and mental state (especially when they are sick, in pain or giving birth to kittens) from other animals or humans to avoid conflicts. Still, they sometimes want to communicate with each other with the help of sounds. Cats like to be out and about at night, and sounds are an especially sensible way of communicating over long distances or when visibility is bad. Certainly many are familiar with the nocturnal concerts of cat sounds.
Cats have learned that humans react well to cat sounds. We humans do not have the same good noses that cats have, and our eyes are also often elsewhere, so that we do not notice, for example, when our furry friends have sneaked into the kitchen and sit in front of their food bowl. When we are working, are occupied with our computers or smart phones or are sleeping, sounds are especially effective. The four-legged companions have understood that and adapted themselves to us. That is why many cats develop a kind of spoken language together with their humans that is mutually understandable.
I have also found that the more I talk to a cat, the more it talks back to me. However, it is important to clarify something here: Do all cats speak the same “language”? Can they understand each other when they communicate with vocal signals? There seem to be signals that are universal and are understood by all cats. But there also seem to be geographic, cultural and breed-based differences. Maybe cats are even influenced by the language or the accent of the people around them. When I give lectures about cat communication, people often come to me afterward with comments and questions. For example, “My cats make entirely different sounds than the ones you played in your lecture. Could it be because I usually speak Japanese at home with them?” Although it has not yet been investigated thoroughly, many researchers are of the opinion that cats can, in fact, develop family, group or neighborhood dialects (Bradshaw, 2013; Leyhausen, 2005). Do cats have dialects or do they develop a set of unique sounds that only their humans can understand? This fascinating question is also the subject of my academic work.
Now we are getting down to it: I would like to explain my work as a phonetician briefly and then help you understand the sounds of cats from that perspective.
WHAT DOES A PHONETICIAN ACTUALLY DO?
My task as a scientist is primarily the investigation of human speech. I have been doing it since 2000. It sounds simple, but some knowledge of the methods is necessary.
My natural curiosity makes my work a lot easier. When I am tracking down a secret, it is not so easy to scare me off the trail. Even if everything is smooth and flawless on the surface, I like to scratch a little bit to see if something else is not hidden there after all.
How do we produce spoken language? How are the sounds of speech (vowels and consonants) produced in different languages and dialects? What do they sound like? These questions are at the core of my work and continue to catch my interest. I am also interested in how sounds, syllables, words, phrases and utterances vary in length (duration), tone (intonation, melody), loudness and voice quality—that is to say, in prosody, as well as what they sound like in different languages and dialects. I have also observed the changes our human voices undergo as we grow older using scientific methods. And it gets even more interesting: How do our emotions influence the way we speak? Why does our speaking style change depending on with whom we speak? Why do we sound different when we speak to young children than we do when we speak to elderly people, when we speak to someone we love and to someone we dislike, or when we speak in private and professional capacities?
We change the intonation or melody of our speech even when we pronounce a simple word, cat, as a question or as a statement. When we say “Cat.” as a statement the intonation generally falls, whereas when we say “Cat?” as a question the intonation rises. The sounds also arrive at our ears in very different versions. For instance, vowels are frequently louder than consonants. In the word kittens, the vowel i is the loudest sound. We emphasize it much more heavily than the other sounds, including the vowel e, which in casual speech often is not pronounced at all, although we use it when we write the word. The four consonants sound very different. Try it yourself! Pronounce the letters k, t, n and s one at a time, and listen very closely. You will be able to hear that the k, which is produced with the tongue farther back than the t, sounds darker (with acoustically low resonances). It becomes even more apparent when you compare the pronunciation of n and s, where the s sounds much brighter than the n. These differences can be explained in that the main sound energy of n can be found on lower frequencies, while s has most of its sound energy in the high frequency bands, and t usually has sound energy on higher frequencies than k. Moreover, did you notice that the i and the n are voiced, as they are produced with vibrating vocal folds (vocal cords), while the k, the t and the s are voiceless? Such phonetic characteristics, as well as a number of others, can be further studied in visual representations depicting the acoustics of speech. At the end of this book starting on page 259, you will find a phonetic alphabet containing all the vowels and consonants I use to describe the sounds of cats in this book.
The following figure shows a three-part diagram which is commonly used by phoneticians. The upper pane shows the waveform (often called an oscillogram), which is a representation of the microphone signal in a recording of me saying the words “Kittens. Kittens?” with my Swedish accent. (I pronounced the first word as a statement, the second as a question.) In the waveform, we can see how loud and how long the different speech sounds are.
In the middle, you can see a spectrogram—it shows how the sound energy of each speech sound is distributed across different frequencies. Because vowels are generally pronounced louder than consonants, they typically also have more energy, and so they show up darker (blacker) in the spectrogram. The s is dark in the upper range of frequencies, but completely white in the bottom range. That means that this s has no energy in the deeper frequencies. Instead, its energy is entirely concentrated in the higher range of frequencies. In an n, exactly the opposite is true—lots of sound energy at the lower frequencies of the spectrogram, but none at all at the top.
In the bottom pane of the diagram, the fundamental frequency (the acoustic term for the pitch contour or melody) of the words is tracked, that is to say, how our tone of voice rises and falls when we speak. You will see right away that the melody of “kittens.” (statement) and “kittens?” (question) is different.
Three phonetic diagrams for the word “kittens.” (statement) and “kittens?” (question): Waveform (top), spectrogram (middle) and fundamental frequency (pitch, melody) (bottom).
Furthermore, we have determined that the same speech sounds are pronounced differently in different dialects and languages. For example, I used a method called electromagnetic articulography, which can be used to track the movements of our speech organs, to determine how vowels are pronounced in different Swedish dialects. I literally looked inside the mouths of different speakers in order to see how they move their tongues, jaws and lips when they pronounce different vowels.
I also translated these vowels into phonetic writing. To aid me I had a system that works in every language: the International Phonetic Alphabet (see Tables 3, 4 and 5 with the phonetic symbols at the end of this book, pages 260–265). Phonetic transcription depicts sounds as they are pronounced. One symbol per sound is the rule. My pronunciation of the word kittens, for example, can be transcribed [′kɪt(ə)n̩ s].
If these phonetic methods work for every human spoken language, I said to myself, they might also work for cat sounds. And, as I have discovered, they usually do.
One of the most commonly used methods of my academic discipline is acoustic analysis. With the help of a computer we can measure different acoustic features of the sounds of speech and compare them. We can measure the length of a sound, such as
