Different modes of listening coexist; this distinction was highlighted by Pierre Schaeffer (1966). We rarely speak spontaneously about the characteristics of sounds, mainly because we focus on other aspects associated with the sound rather than the sound itself. We usually focus on the identification of the source that produced the sound, or on the meaning associated with a sound. It is difficult to speak about the characteristics of sounds because there is a lack of sound lexicons to promote communication on sounds. There is also a lack of consensual definitions for the words relevant to describe sounds, and there is a lack of good sound examples to experience this relationship between words and sounds. With the SpeaK project, we propose a collaborative platform for organizing, presenting, and sharing sound lexicons combining words, definitions and sound examples. We invite contributors, sound researchers, sound designers, ... to use this platform to create and share sound lexicons. The goal is 1) to improve sound perception because verbalization help to focus on sound, 2) to improve sound communication because sounds are sensations related to words, and 3) to improve specific vocabulary related to different categories of sounds. The collaborative platform proposed is a web application, SpeaK for Web, allowing contributors to create and share lexicons online related to a specific project. The lexicon words4sounds.speak is the first sound lexicon available for SpeaK. It provides a list of words frequently used to describe the perceived characteristics of sounds based on by Maxime Carron PhD, with a definition and sound examples for each word. This lexicon helps to acquire a vocabulary to communicate on the perceived characteristics of a sound, and to foster the perception of these characteristics by listening to sound examples. This lexicon is also used for improving communication in a sound design process.