Momel
Encyclopedia
Momel is an algorithm developed by Daniel Hirst and Robert Espesser at the CNRS Laboratoire Parole et Langage
, Aix-en-Provence
:
for the analysis and synthesis of intonation patterns.
curves for the study of intonation needs to take into account the fact that speakers are simultaneously producing an intonation pattern and a sequence of syllables made up of segmental phones. The actual raw fundamental frequency curves which can be analysed acoustically are the result of an interaction between these two components and this makes it difficult to compare intonation patterns when they are produced with different segmental material. Compare for example the intonation patterns on the utterances Its for papa and It's for mama.
The quadratic spline function used to model the macromelodic component is defined by a sequence of target points, (couples
curves with the spline knot occurring (by default) at the midway point between the two targets. The first derivative of the curve thus defined is zero at each target point and the two parabolas have the same value and same derivative at the spline knot. This in fact defines the most simple mathematical function for which the curves are both continuous and smooth.
On the other hand, the utterances "For Mama!" and "For Mama?" could be modelled with the same micromelodic profile but with different target point, while "For Papa!" and "For Papa?" would also have the same micromelodic profile but which would be different from those of the first pair.
The Momel algorithm derives what its authors refer to as a phonetic representation of an intonation pattern which is neutral with respect to speech production and speech perception since while not explicitly derived from a model of either production or perception it contains sufficient information to allow it to be used as input to models of either process. The relatively theory-neutral nature of the algorithm has allowed it to be used as a first step in deriving representations such as those of the Fujisaki model (Mixdorff 1999), ToBI
(Maghbouleh 1999, Wightman & al. 2000) or INTSINT
(Hirst & Espesser 1993, Hirst et al. 2000).
Laboratoire Parole et Langage
Laboratoire parole et langage is a CNRS laboratory affiliated with Université de Provence in Aix-en-Provence.Head: Christine Meunier & Noël Nguyen-Activities:* * * *...
, Aix-en-Provence
Aix-en-Provence
Aix , or Aix-en-Provence to distinguish it from other cities built over hot springs, is a city-commune in southern France, some north of Marseille. It is in the region of Provence-Alpes-Côte d'Azur, in the département of Bouches-du-Rhône, of which it is a subprefecture. The population of Aix is...
:
for the analysis and synthesis of intonation patterns.
Purpose
The analysis of raw fundamental frequencyFundamental frequency
The fundamental frequency, often referred to simply as the fundamental and abbreviated f0, is defined as the lowest frequency of a periodic waveform. In terms of a superposition of sinusoids The fundamental frequency, often referred to simply as the fundamental and abbreviated f0, is defined as the...
curves for the study of intonation needs to take into account the fact that speakers are simultaneously producing an intonation pattern and a sequence of syllables made up of segmental phones. The actual raw fundamental frequency curves which can be analysed acoustically are the result of an interaction between these two components and this makes it difficult to compare intonation patterns when they are produced with different segmental material. Compare for example the intonation patterns on the utterances Its for papa and It's for mama.
Algorithm
The Momel algorithm attempts to solve this problem by factoring the raw curves into two components:- a macromelodic component - modelled as a quadraticQuadraticIn mathematics, the term quadratic describes something that pertains to squares, to the operation of squaring, to terms of the second degree, or equations or formulas that involve such terms...
spline functionSpline (mathematics)In mathematics, a spline is a sufficiently smooth piecewise-polynomial function. In interpolating problems, spline interpolation is often preferred to polynomial interpolation because it yields similar results, even when using low-degree polynomials, while avoiding Runge's phenomenon for higher...
. This is assumed to correspond to the global pitch contourPitch contourIn linguistics, speech synthesis, and music, the pitch contour of a sound is a function or curve that tracks the perceived pitch of the sound over time....
of the utterance, and which is independent of the nature of the constituent phonemes. The underlying hypothesis is that this macromelodic component is, unlike raw fundamental frequency curves, both continuous and smoothSmoothSmooth means having a texture that lacks friction. Not rough.Smooth may also refer to:-In mathematics:* Smooth function, a function that is infinitely differentiable; used in calculus and topology...
. It corresponds approximately to what we produce if we hum an utterance instead of speaking it.
- a micromelodic component consisting of deviations from the macromelodic curve - called a micromelodic profile. This residual curve is assumed to be determined entirely by the segmental constituents of the utterance and to be independent of the macromelodic component.
The quadratic spline function used to model the macromelodic component is defined by a sequence of target points, (couples
Parabola
In mathematics, the parabola is a conic section, the intersection of a right circular conical surface and a plane parallel to a generating straight line of that surface...
curves with the spline knot occurring (by default) at the midway point between the two targets. The first derivative of the curve thus defined is zero at each target point and the two parabolas have the same value and same derivative at the spline knot. This in fact defines the most simple mathematical function for which the curves are both continuous and smooth.
Implications
On the one hand, two utterances "For Mama!" and "For Papa!" could thus be modelled with the same target points (hence the same macromelodic component) while "For Mama?" and "For Papa?" would also have the same target points but which would probably be different from those of the first pair.On the other hand, the utterances "For Mama!" and "For Mama?" could be modelled with the same micromelodic profile but with different target point, while "For Papa!" and "For Papa?" would also have the same micromelodic profile but which would be different from those of the first pair.
The Momel algorithm derives what its authors refer to as a phonetic representation of an intonation pattern which is neutral with respect to speech production and speech perception since while not explicitly derived from a model of either production or perception it contains sufficient information to allow it to be used as input to models of either process. The relatively theory-neutral nature of the algorithm has allowed it to be used as a first step in deriving representations such as those of the Fujisaki model (Mixdorff 1999), ToBI
ToBI
ToBI is a set of conventions for transcribing and annotating the prosody of speech. 'ToBI' is sometimes used to refer to the conventions used for describing English specifically, but ToBI systems have been defined for a number of other languages, for example J-ToBI refers to the ToBI conventions...
(Maghbouleh 1999, Wightman & al. 2000) or INTSINT
INTSINT
INTSINT is an acronym for INternational Transcription System for INTonation.It was originally developed by Daniel Hirst in his 1987 thesis as a prosodic equivalent of the International Phonetic Alphabet, and the INTSINT alphabet was subsequently used in Hirst & Di Cristo 1998 in just over half of...
(Hirst & Espesser 1993, Hirst et al. 2000).