Motivated by the potential of speech modification for the enhancement of intelligibility in noisy environments, we study the acoustic characteristics of speech produced in the context of critical announcements made in noisy listening situations. A corpus of 3 speakers producing 20 Marathi train station announcements is analysed for articulatory-acoustic and prosodic differences between speech in noise and in quiet. It is observed that apart from the global changes that are characteristic of increased vocal effort, the intonation associated with phrase and word accents is consistently modified. Listening tests with modified speech suggest that spectral shaping and F0 modifications that are linguistically valid contribute constructively to increased intelligibility in noise, as measured in an information extraction task.