A method implemented by one or more processors, the method comprising: detecting, via one or more microphones of a client device of a given user, spoken input of the given user; determining, based on at least one user interface input at a client device of a given user, a first textual segment for conveying in a conversation in which the given user is a participant, the at least one user interface input comprising the spoken input and the determining comprising processing (254A1) the spoken input using a speech recognition model to generate the first textual segment; identifying an additional participant in the conversation, the additional participant being in addition to the given user and being in an environment with the given user; determining (258A, 258A1) one or more prosodic properties based on at least one attribute of a relationship between the given user and the additional participant; generating synthesized speech audio data that includes synthesized speech that incorporates the first textual segment and that is synthesized with the one or more prosodic properties, wherein generating the synthesized speech audio data comprises synthesizing the synthesized speech with the one or more prosodic properties responsive to determining the prosodic properties based on the attribute of the relationship between the given user and the additional participant; and in response to receiving user input from the given user, at the client device, affirming that the synthesized speech should be rendered, causing the synthesized speech to be rendered via one or more speakers of the client device and/or an additional client device in the environment, wherein the rendered synthesized speech (476, 376) is audibly perceptible to the additional participant. detecting, via one or more microphones of a client device of a given user, spoken input of the given user; determining, based on at least one user interface input at a client device of a given user, a first textual segment for conveying in a conversation in which the given user is a participant, the at least one user interface input comprising the spoken input and the determining comprising processing (254A1) the spoken input using a speech recognition model to generate the first textual segment; identifying an additional participant in the conversation, the additional participant being in addition to the given user and being in an environment with the given user; determining (258A, 258A1) one or more prosodic properties based on at least one attribute of a relationship between the given user and the additional participant; generating synthesized speech audio data that includes synthesized speech that incorporates the first textual segment and that is synthesized with the one or more prosodic properties, wherein generating the synthesized speech audio data comprises synthesizing the synthesized speech with the one or more prosodic properties responsive to determining the prosodic properties based on the attribute of the relationship between the given user and the additional participant; and in response to receiving user input from the given user, at the client device, affirming that the synthesized speech should be rendered, causing the synthesized speech to be rendered via one or more speakers of the client device and/or an additional client device in the environment, wherein the rendered synthesized speech (476, 376) is audibly perceptible to the additional participant.