# Prosody in Mathtalk

(The sound recordings in the examples on these pages have been recorded to high and low qualities. The high quality ones sound better - but will take longer to arrive. You can choose which quality you want to hear by selecting either 'High' or 'Low'.)

Synthetically spoken algebra can sound relentless without prosody. For instance, the following example 4x4 + 3x3 + 2x2 + 2x + 1 = 0 sounds like this (High, Low) without prosody. However, simply by adding pauses, pitch changes and amplitude - according to a set of rules for algebraic prosody - the same equation now sounds like this (High, Low).

As well as making the listening task easier, prosody can be used to indicate the syntactic structure of an expression. The syntactically simple expression 3x + 4 = 7 is presented using prosody like this (High, Low). The introduction of parentheses into the same expression to give 3(x + 4) = 7 can be indicated prosodically by changing the pattern of pauses, pitch changes, tempo and amplitude, like this (High, Low)

One advantage of using prosody is the reduction in the amount of speech. A traditional method of indicating syntactic structure is to insert lexical cues at points of grouping ambiguity. The expression using these lexical cues, sounds like this (High, Low). However, prosody alone can indicate the prosody of the expression, like this (High, Low).

Whilst prosody can successfully convey most syntactic structure, some information may be lost in very complex expressions. This fact, together with only having the expression spoken all at once and the passive nature of listening means prosody alone does not enable active reading. The provision of control over information flow aims to provide active reading of algebra notation.

Browsing and navigating in Mathtalk.
Earcons: auditory glances in Mathtalk.
The Maths Project.