About

Every alphabetic writing system partitions its characters into vowels and consonants. English uses 21 consonant letters out of 26 total - roughly 80.8% of the alphabet. Replacing consonants exposes the vowel skeleton of text, a technique used in phonological analysis, language learning drills, and creative cipher construction. Miscounting consonants or forgetting edge cases like y (which functions as both vowel and consonant depending on position) leads to flawed datasets in corpus linguistics work. This tool applies character-level replacement with O(n) complexity, preserves original letter casing when desired, and handles the full English consonant set: b, c, d, f, g, h, j, k, l, m, n, p, q, r, s, t, v, w, x, z. The letter y is configurable - include or exclude it depending on your phonological framework.

Limitations: this tool operates on orthographic characters, not phonemes. The word "through" contains the consonant cluster thr orthographically but a single onset phoneme /θɹ/ phonetically. For IPA-level analysis, a dedicated phonemic parser is required. Pro tip: when using this for language learning, compare the vowel skeleton output against the original to train consonant recognition speed.

Formulas

The replacement algorithm iterates through each character c_i in the input string S of length n. For each character, it checks membership in the consonant set C.

output_i =

{

R if lower(c_i) ∈ Cc_i otherwise

Where R = replacement character (user-defined), C = {b, c, d, f, g, h, j, k, l, m, n, p, q, r, s, t, v, w, x, z} (optionally ∪ {y}), and n = len(S).

The consonant replacement ratio is computed as:

ratio = count(c_i ∈ C)n × 100%

Time complexity: O(n). Space complexity: O(n) for the output string. Set lookup is O(1) amortized via hash set.

Reference Data

Letter	Type	IPA Example	Frequency in English (%)	Notes
b	Consonant	/b/ - bat	1.49	Voiced bilabial plosive
c	Consonant	/k/ or /s/	2.78	Hard before a, o, u; soft before e, i
d	Consonant	/d/ - dog	4.25	Voiced alveolar plosive
f	Consonant	/f/ - fish	2.23	Voiceless labiodental fricative
g	Consonant	/ɡ/ or /dʒ/	2.02	Hard or soft depending on context
h	Consonant	/h/ - hat	6.09	Voiceless glottal fricative; silent in some words
j	Consonant	/dʒ/ - jam	0.15	Voiced postalveolar affricate
k	Consonant	/k/ - kite	0.77	Silent before n (e.g., "knee")
l	Consonant	/l/ - lamp	4.03	Lateral approximant
m	Consonant	/m/ - map	2.41	Bilabial nasal
n	Consonant	/n/ - net	6.75	Alveolar nasal
p	Consonant	/p/ - pen	1.93	Voiceless bilabial plosive
q	Consonant	/k/ - queen	0.10	Almost always followed by u
r	Consonant	/ɹ/ - red	5.99	Alveolar approximant (rhotic)
s	Consonant	/s/ or /z/	6.33	Most common consonant letter
t	Consonant	/t/ - top	9.06	Most frequent consonant in English
v	Consonant	/v/ - van	0.98	Voiced labiodental fricative
w	Consonant	/w/ - win	2.36	Labial-velar approximant
x	Consonant	/ks/ - fox	0.15	Typically represents cluster /ks/
y	Ambiguous	/j/ or /iː/	1.97	Consonant at syllable onset; vowel elsewhere
z	Consonant	/z/ - zoo	0.07	Least frequent consonant
a	Vowel	/æ/ - cat	8.17	Open front unrounded
e	Vowel	/ɛ/ - bed	12.70	Most frequent letter overall
i	Vowel	/ɪ/ - sit	6.97	Close front unrounded
o	Vowel	/ɒ/ - hot	7.51	Open back rounded
u	Vowel	/ʌ/ - cup	2.76	Open-mid back unrounded

Frequently Asked Questions

In English phonology, y functions as a consonant when it appears at the beginning of a syllable (e.g., "yes", "beyond") and as a vowel when it appears in the nucleus (e.g., "gym", "myth"). This tool provides a toggle to include or exclude y from the consonant set. For most corpus linguistics work, treating y as a consonant is the default convention. For phonological vowel skeleton analysis, exclude it.

The current implementation targets the 26-letter English alphabet. Characters with diacritics (e.g., ñ, ç, ß) and letters from other scripts (Cyrillic, Greek, Arabic) are passed through unchanged. If your text contains such characters, they will remain in the output unmodified. Extend the consonant set manually by editing the replacement character mapping for multilingual support.

When case preservation is enabled, the tool checks whether the original consonant was uppercase. If so, the replacement character is converted to uppercase before insertion. For example, replacing consonants with * in "Hello" yields "*e**o" without case preservation, but since * has no case, the output is identical. Case preservation matters when the replacement character is itself a letter - replacing with x would yield "Xexxo" with preservation on, versus "xexxo" with it off.

Setting the replacement to an empty string effectively strips all consonants from the text, leaving only vowels, digits, punctuation, and whitespace. This produces a vowel skeleton useful for phonological pattern analysis. For instance, "structure" becomes "uuue" - exposing the underlying vowel pattern.

Yes. The tool accepts multi-character replacement strings. Each consonant will be replaced by the full string. For example, replacing with "[*]" transforms "cat" into "[*]a[*]". Be aware this changes the output length: if your input has k consonants and the replacement string has length m, the output length becomes n − k + k × m.

In standard English prose, approximately 62% of alphabetic characters are consonants (based on letter frequency analysis of large corpora). The reference table shows individual letter frequencies from Lewand's cryptographic analysis of 40,000 words. The tool's statistics panel reports the actual consonant ratio of your specific input, which may deviate from the corpus average depending on vocabulary and style.