Thai Kedmanee keyboard layout
The Thai Kedmanee keyboard layout, named after the winner of a 1970 Thai typing speed competition, Suwanprasert Ketmanee, is the predominant input method for typing the Thai script on computers and typewriters in Thailand, mapping the 44 Thai consonants, 15 vowel symbols, 4 tone marks, and various diacritics onto a standard QWERTY-style keyboard using shift and dead-key combinations to produce stacked syllable forms.[1] It originated in the early 20th century from typewriter designs, evolving from innovations like Edwin Hunter's 1891 Thai typewriter and later refinements by Thai engineers such as Plueng Suthikham in the 1920s, before being adapted for digital use.[1] Codified as the official standard by the Thai Industrial Standards Institute (TISI) under TIS 820-2531 in 1988 for computer keyboards, the layout was updated in 1995 to TIS 820-2538, which introduced minor modifications for better compatibility while retaining the core structure of four rows: numerals on top, consonants and high vowels in the second row, low vowels and tones in the third, and additional symbols in the bottom row.[2] This design supports touch-typing but has been noted for ergonomic imbalances, with approximately 70% of keystrokes falling on the right hand due to the frequency of certain Thai characters.[1] Despite alternatives like the Pattachote layout, Kedmanee remains the de facto standard across operating systems such as Windows and macOS, as well as hardware from manufacturers like Microsoft, due to its widespread adoption among Thai users and official endorsement.[3][2][4]History
Origins and Development
The introduction of Thai typewriters in the early 20th century marked a significant step in standardizing Thai script input, beginning with models developed in the 1890s that featured cumbersome seven-row designs with up to 84 keys. These early typewriters, pioneered by American inventor Edwin Hunter McFarland in collaboration with Smith Premier, were adapted from English keyboards but struggled with the complexities of Thai's 44 consonants, 15 vowel symbols, and tone marks, often excluding less common characters like Khor Khuat and Kor Kon.[1] By the 1920s, efforts to streamline these machines, led by Thai engineer Plueng Suthikham and the Smith Premier Store, resulted in more practical four-row layouts, reducing the key count to 42-46 while incorporating multifunctional assignments to handle the full Thai alphabet through shift mechanisms and dead keys.[1] This shift was driven by practical constraints of typewriter manufacturing, such as limited space and mechanical simplicity, influencing the foundational arrangement that would evolve into the Kedmanee layout.[5] The Kedmanee layout emerged in the early 1930s as a refinement of these four-row typewriter designs, attributed to Thai engineer Suwanprasert Kedmanee, an employee of Remington Typewriter Company in Thailand. Named after its designer, the layout was introduced around 1932 to enhance typing efficiency on mechanical typewriters, prioritizing faster input speeds and ease of use by strategically placing commonly used Thai characters in accessible positions.[5] Key design principles focused on the ergonomic demands of Thai typography, with high-frequency consonants and vowels positioned on the home row to minimize finger travel, informed by the language's character usage patterns where certain letters like "k," "m," and short vowels appear disproportionately in everyday text.[1] This approach addressed the limitations of earlier models, such as the imbalance in hand usage, though it retained some asymmetries that later drew criticism for favoring right-hand dominance.[1] As personal computers proliferated in Thailand during the 1980s, the Kedmanee layout transitioned from typewriter hardware to digital input methods, preserving its core mappings to maintain familiarity for users accustomed to mechanical typing. Initial adaptations mapped the 44 Thai characters onto standard QWERTY keyboards using software modifiers, accommodating the expanded key availability while inheriting the multifunctional logic from typewriters. This preservation ensured continuity in typing practices, with formal codification as Thai Industrial Standard 820-2531 occurring in 1988, followed by updates in the 1990s to incorporate additional symbols.[1]Standardization and Adoption
Formal standardization for computer keyboards occurred in 1988 through Thai Industrial Standard (TIS) 820-2531, issued by the Thai Industrial Standards Institute (TISI), which adapted the typewriter-based Kedmanee design to digital interfaces.[1] An update in 1995, designated TIS 820-2538, introduced minor adjustments such as adding keys for rare symbols like Anghankhu (๚), Fongman (๏), Khomut (๛), and Yamakkan (อ๎), along with changes to positions like the Baht sign (฿) for better compatibility with computer technologies.[2][6] Having become the de facto standard for Thai typewriters by the mid-20th century, Kedmanee was dominant in Thailand by the 1970s, integral to education, government operations, and media production, with virtually all Thai keyboards adhering to it by the early 2000s.[2] As the official TIS standard, it is required for use in government documents and public sector applications, supporting consistent Thai language input and contributing to national literacy efforts by standardizing access to the script's complex consonants, vowels, and tones.[1][3]Layout Design
Physical Arrangement
The Thai Kedmanee keyboard layout is based on the standard 104-key ANSI physical keyboard configuration, adapted with Thai-specific character overlays while retaining the familiar QWERTY frame for compatibility with existing hardware.[3] This arrangement allows for the integration of Thai script elements onto a conventional computer keyboard without requiring specialized hardware modifications.[2] The layout organizes keys across multiple rows to optimize access to Thai phonetic components. The number row accommodates diacritics and short vowels like ์ (thanthakhat) on '1' and ั (sara a) on '2', with Thai numerals accessed via Shift (e.g., '1' Shift = ๑). Tone marks are positioned on the alphabetic rows, such as ่ (mai ek) on 'J', ้ (mai tho) on 'H', ๊ (mai tri) on 'U', and ๋ (mai chattawa) on shifted 'J', for integration during syllable entry. The home row contains a mix of common consonants (e.g., ห on 'S', ก on 'D', ด on 'F') and vowels/diacritics (e.g., ั on 'A', า on 'K'), supporting efficient stacking. The top and bottom rows handle additional vowels, consonants, and symbols, balancing frequency-based access derived from typewriter designs.[7][3] Modifier keys such as Shift are used to access uppercase letters, additional tones, variant forms, and Thai digits, while Alt (or AltGr on some systems) enables entry of supplementary characters like rare consonants. The standard version does not include a dedicated Thai shift key, relying instead on these conventional modifiers to generate the full range of symbols.[3] This design, codified in Thai Industrial Standard 820-2538 (1995), maps 44 Thai consonants, 18 vowel symbols (forming 32 combinations), and 4 tone marks across approximately 60 keys, as illustrated in standard diagrams of the layout.[2] The row structure draws from earlier Thai typewriter designs, adapting their phonetic grouping for modern computational use.[2]Character Assignments
The Thai Kedmanee keyboard layout maps the 44 Thai consonants to various keys on the QWERTY-style arrangement, prioritizing high-frequency characters based on typewriter precedents for overall efficiency despite a known right-hand bias. High-frequency consonants such as ฟ (fo fa), ก (ko kai), and ด (do dek) are placed on the left home row keys like 'A', 'D', and 'F', while others like ร (ro ruea), น (no nen), and ส (so sua) occupy right-side positions on 'I', 'O', and 'L'. Less frequent consonants, including ฌ (cho chaning) on 'G' and ศ (so rala) on shifted 'L', are assigned to home and shifted keys. This assignment facilitates input for everyday Thai text, with software reordering elements for visual stacking.[7][2] Vowels and diacritics, which form 32 possible combinations in Thai script, are primarily assigned to the number row and alphabetic keys to allow stacking above, below, or beside consonants for complex syllables. For instance, the number row unshifted includes lower vowels and diacritics like QWERTY '1' = ์ (silent mark or thanthakhat) and '2' = ั (sara a), while upper vowels such as ี (sara i long) on 'U' and ู (sara u long) on shifted '6' appear on top row or modifier combinations. Combining rules require vowels to be typed before or after the base consonant, with software reordering them visually according to Thai orthographic conventions, such as placing leading vowels (e.g., เ on 'G') to the left and trailing ones (e.g., า on 'K') to the right. Dead key behaviors enable diacritics like ำ (sara am) on 'E' to combine without advancing the cursor. Input sequences are automatically reordered by the input method for proper display.[3][2] Tone marks, essential for the four tones in Thai (mid unmarked), are mapped to home and top row keys with or without Shift for easy access during syllable construction. The low tone (mai ek: ่ on 'J'), falling tone (mai tho: ้ on 'H'), high tone (mai tri: ๊ on 'U'), and rising tone (mai chattawa: ๋ on shifted 'J') overlay vowels or consonants without altering base spacing. These marks follow vowels in input sequence and are rendered above the affected character in output.[2][7] Special characters include Thai digits on shifted number keys (e.g., shifted '0' = ๐ for zero) and adapted punctuation like ฿ (baht symbol) on shifted ';', integrated to support financial and typographic needs while maintaining compatibility with English symbols on unmodified keys. Additional diacritics, such as mai yamok (ๆ) on 'Q', and Pali/Sanskrit marks are accessible via less common keys or AltGr combinations in extended implementations.[3]| Category | Example Mappings (QWERTY Key = Thai Character) | Notes |
|---|---|---|
| Consonants (High-Frequency) | 'A' = ฟ, 'D' = ก, 'F' = ด, 'I' = ร, 'L' = ส, 'O' = น | Distribution across hands; right-side emphasis for some common ones. |
| Vowels/Diacritics | '1' = ์, '2' = ั, 'U' = ี, 'E' = ำ | Number row for short forms; combining with base consonants; software reordering. |
| Tone Marks (Unshifted/Shifted) | 'J' = ่ (mai ek), 'H' = ้ (mai tho), 'U' = ๊ (mai tri) | Applied after vowels; four tones total, mid unmarked. |
| Digits/Special | '1' Shift = ๑, '0' Shift = ๐, ']' = ฿ | Thai numerals and currency on shifts. |