Level	Biofeedback frequency	Mode of elicitation	Stimulus complexity
1	100%	Imitate clinician's model	1 syllable simple
2	50%	Imitate clinician's model	1 syllable simple
3	50%	Read independently	1 syllable simple
4	50%	Read independently	1 syllable with competing /l/ or /w/
5	0%	Read independently	1 syllable with competing /l/ or /w/
6	0%	Imitation with prosodic manipulation	1 syllable with competing /l/ or /w/
7	0%	Imitation with prosodic manipulation	2 syllables simple
8	0%	Independent reading with prosodic manipulation	2 syllables simple
9	0%	Independent reading with prosodic manipulation	2 syllables with competing /l/ or /w/
10	0%	Independent reading with prosodic manipulation	Words in carrier phrases
11	0%	Independent reading with prosodic manipulation	Words in sentences
12	0%	Independent reading with prosodic manipulation	Sentences with multiple /r/ targets

Note. Parameters (represented in columns) change on a rotating basis between levels; the parameter that was changed in a given level is in bold.