Apparatus, comprising: a network interface; and a processor, configured: to receive, via the network interface, a signal representing speech of a subject who suffers from a pulmonary condition related to accumulation of excess fluid, to identify one or more properties of a frequency spectrum of the speech, wherein the properties include at least one formant frequency of the speech, to assess, in response to the properties, a status of the pulmonary condition, and to generate, in response thereto, an output indicative of the status of the pulmonary condition; characterized in that the processor is configured to identify the formant frequency by: for each frame of the signal: computing a cepstrum of the frame, subsequently, applying a low-pass cepstral lifter to the cepstrum of the frame, subsequently, inverse-transforming the liftered cepstrum to a frequency domain, and subsequently, identifying a formant frequency of the frame, by identifying a peak of the inverse-transformed liftered cepstrum, and identifying the formant frequency, based on the respective formant frequencies of the frames. a network interface; and a processor, configured: to receive, via the network interface, a signal representing speech of a subject who suffers from a pulmonary condition related to accumulation of excess fluid, to identify one or more properties of a frequency spectrum of the speech, wherein the properties include at least one formant frequency of the speech, to assess, in response to the properties, a status of the pulmonary condition, and to generate, in response thereto, an output indicative of the status of the pulmonary condition; to receive, via the network interface, a signal representing speech of a subject who suffers from a pulmonary condition related to accumulation of excess fluid, to identify one or more properties of a frequency spectrum of the speech, wherein the properties include at least one formant frequency of the speech, to assess, in response to the properties, a status of the pulmonary condition, and to generate, in response thereto, an output indicative of the status of the pulmonary condition; characterized in that the processor is configured to identify the formant frequency by: for each frame of the signal: computing a cepstrum of the frame, subsequently, applying a low-pass cepstral lifter to the cepstrum of the frame, subsequently, inverse-transforming the liftered cepstrum to a frequency domain, and subsequently, identifying a formant frequency of the frame, by identifying a peak of the inverse-transformed liftered cepstrum, and identifying the formant frequency, based on the respective formant frequencies of the frames. for each frame of the signal: computing a cepstrum of the frame, subsequently, applying a low-pass cepstral lifter to the cepstrum of the frame, subsequently, inverse-transforming the liftered cepstrum to a frequency domain, and subsequently, identifying a formant frequency of the frame, by identifying a peak of the inverse-transformed liftered cepstrum, and computing a cepstrum of the frame, subsequently, applying a low-pass cepstral lifter to the cepstrum of the frame, subsequently, inverse-transforming the liftered cepstrum to a frequency domain, and subsequently, identifying a formant frequency of the frame, by identifying a peak of the inverse-transformed liftered cepstrum, and identifying the formant frequency, based on the respective formant frequencies of the frames.